1,371 results
Search Results
2. Use of a Web-based Questionnaire in the Black Women's Health Study.
- Author
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Russell, Cordelia W., Boggs, Deborah A., Palmer, Julie R., and Rosenberg, Lynn
- Subjects
AGE distribution ,ANALYSIS of variance ,BLACK people ,COST control ,LONGITUDINAL method ,QUESTIONNAIRES ,RESEARCH funding ,SURVEYS ,WOMEN ,WORLD Wide Web ,CONTENT mining ,ECONOMICS - Abstract
The authors assessed the utility and cost-effectiveness of using a World Wide Web-based questionnaire in a large prospective cohort study, the Black Women's Health Study (BWHS). In 1995, 59,000 African-American women were recruited into the BWHS through a paper questionnaire. Follow-up paper questionnaires have been mailed every 2 years since then. During the 2003, 2005, and 2007 questionnaire cycles, participants were given the option of completing a Web-based questionnaire. The cost of developing and processing a returned paper questionnaire was 4 times that of a returned Web questionnaire, primarily because of return postage costs and greater processing time for paper questionnaires. The proportion of respondents who completed a Web questionnaire doubled from 2003 to 2007, from 10.1% to 19.9%, but the characteristics of those completing the Web questionnaire remained the same. Web response was greatest at younger ages (20.9% of those aged <30 years) and declined with age to 3.6% among women aged 60 years or more. Web questionnaires were filled out more completely than paper questionnaires, regardless of the sensitivity of a question. The use of a Web questionnaire in the BWHS resulted in cost savings and more complete responses. Although there are advantages to using a Web questionnaire, the use of multiple means of soliciting questionnaire responses is still needed. [ABSTRACT FROM PUBLISHER]
- Published
- 2010
- Full Text
- View/download PDF
3. Commentary: On R. A. Fisher's paper 'The causes of human variability', 1918.
- Author
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Edwards, A W F
- Subjects
ANALYSIS of variance ,NATURAL selection ,BIOLOGICAL evolution ,GENE expression - Published
- 2019
- Full Text
- View/download PDF
4. Discussion on the paper by Heffernan and Tawn.
- Author
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Smith, Richard L., Coles, Stuart, Ferro, Christopher, Butler, Adam, Anderson, Clive, Sahu, S. K., Mardia, K. V., Dupuis, Debbie J., Drees, Holger, Atkinson, Anthony C., Beirlant, J., Goegebeur, Y., Boldi, M.-O., Davison, A. C., Chatfield, C., Ledford, Anthony, Pen, L., Qi, Y., and Segers, Johan
- Subjects
DISTRIBUTION (Probability theory) ,RANDOM variables ,MATHEMATICS ,MULTIVARIATE analysis ,ANALYSIS of variance ,MATHEMATICAL statistics - Abstract
Discusses the multivariate extreme value theory that emerged in several studies in the 1950s during the popularity of asymptomatic distributions in probability. Examination on the mathematical abstraction of the formulation of the theory; Discovery of the deficiencies of this appraoch during the 1990s; Information on proposed correction to the deficiencies of the approach.
- Published
- 2004
- Full Text
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5. What Moves Stock Prices? The Roles of News, Noise, and Information.
- Author
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Brogaard, Jonathan, Nguyen, Thanh Huong, Putnins, Talis J, and Wu, Eliza
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STOCK prices ,STOCK price forecasting ,RATE of return ,RATE of return on stocks ,ANALYSIS of variance ,DECOMPOSITION method ,EFFICIENT market theory ,FINANCIAL markets - Abstract
We develop a return variance decomposition model to distinguish the roles of different types of information and noise in stock price movements. We disentangle four components: noise, private firm-specific information revealed through trading, firm-specific information revealed through public sources and market-wide information. Overall, we find that 31 |$\%$| of the return variance is from noise, 24 |$\%$| from private firm-specific information, 37 |$\%$| from public firm-specific information and 8 |$\%$| from market-wide information. Since the mid-1990s, there has been a dramatic decline in noise and an increase in firm-specific information, consistent with increasing market efficiency. The Internet Appendix that accompanies this paper can be obtained here: https://bit.ly/3FcV9UR [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
6. A century of variance.
- Author
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Charlesworth, Brian and Edwards, Anthony W. F.
- Subjects
ANALYSIS of variance ,COST analysis ,COMMON method variance ,QUANTITATIVE research - Abstract
Brian Charlesworth and Anthony W. F. Edwards mark the 100th anniversary of a paper by R. A. Fisher, which introduced the statistical term “variance”. What followed was a whole new field of statistical analysis [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
7. Effects of Breathing Frequency and Flow Rate on the Total Inward Leakage of an Elastomeric Half-Mask Donned on an Advanced Manikin Headform.
- Author
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He, Xinjian, Grinshpun, Sergey A., Reponen, Tiina, McKay, Roy, Bergman, Michael S., and Zhuang, Ziqing
- Subjects
ARTIFICIAL respiration equipment ,ARTIFICIAL respiration ,AEROSOLS ,ANALYSIS of variance ,ELASTOMERS ,HUMAN anatomical models ,PARTICLES ,RESEARCH funding ,RESPIRATION ,RESPIRATORY measurements ,STATISTICS ,DATA analysis ,DATA analysis software ,DESCRIPTIVE statistics ,IN vitro studies - Abstract
Objectives: The objective of this study was to investigate the effects of breathing frequency and flow rate on the total inward leakage (TIL) of an elastomeric half-mask donned on an advanced manikin headform and challenged with combustion aerosols. Methods: An elastomeric half-mask respirator equipped with P100 filters was donned on an advanced manikin headform covered with life-like soft skin and challenged with aerosols originated by burning three materials: wood, paper, and plastic (polyethylene). TIL was determined as the ratio of aerosol concentrations inside (Cin) and outside (Cout) of the respirator (Cin/Cout) measured with a nanoparticle spectrometer operating in the particle size range of 20–200nm. The testing was performed under three cyclic breathing flows [mean inspiratory flow (MIF) of 30, 55, and 85 l/min] and five breathing frequencies (10, 15, 20, 25, and 30 breaths/min). A completely randomized factorial study design was chosen with four replicates for each combination of breathing flow rate and frequency. Results: Particle size, MIF, and combustion material had significant (P < 0.001) effects on TIL regardless of breathing frequency. Increasing breathing flow decreased TIL. Testing with plastic aerosol produced higher mean TIL values than wood and paper aerosols. The effect of the breathing frequency was complex. When analyzed using all combustion aerosols and MIFs (pooled data), breathing frequency did not significantly (P = 0.08) affect TIL. However, once the data were stratified according to combustion aerosol and MIF, the effect of breathing frequency became significant (P < 0.05) for all MIFs challenged with wood and paper combustion aerosols, and for MIF = 30 l/min only when challenged with plastic combustion aerosol. Conclusions: The effect of breathing frequency on TIL is less significant than the effects of combustion aerosol and breathing flow rate for the tested elastomeric half-mask respirator. The greatest TIL occurred when challenged with plastic aerosol at 30 l/min and at a breathing frequency of 30 breaths/min. [ABSTRACT FROM AUTHOR]
- Published
- 2014
8. SHARPEST: the atmospheric turbulence profiling experiment using Shack–Hartmann sensor at the Subaru telescope.
- Author
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Ogane, Hajime, Ono, Yoshito, Minowa, Yosuke, Oya, Shin, Terao, Koki, Akasawa, Takumi, Homan, Riki, and Akiyama, Masayuki
- Subjects
- *
ATMOSPHERIC turbulence , *ADAPTIVE optics , *TELESCOPES , *DETECTORS , *ANALYSIS of variance , *VERY large array telescopes - Abstract
Atmospheric turbulence profile plays an important role in designing and operating adaptive optics (AO) systems with multiple laser guide stars. To obtain representative free atmospheric profiles and resolved ground layer profiles for future AO systems at the Subaru telescope, we are conducting the Shack–Hartmann Atmospheric tuRbulence Profiling Experiment at the Subaru Telescope project. In this project, we develop a turbulence profiler comprising two Shack–Hartmann (SH) sensors to observe a pair of bright stars through the Subaru telescope with high spatial sampling by 2 cm subapertures. We perform two analyses on the SH spot data: variance analysis on the spot scintillation for free atmospheric profiles, and on the spot slope for ground layer profiles. This paper introduces the initial results of free atmospheric profiles as well as total seeing values and wind profiles obtained by the first two engineering runs. The free atmospheric profiles reconstructed by the two independent SH sensors show good agreement. The results are also consistent with simultaneous measurements by another profiler except for turbulence strength at ∼1 km, which is explained by an overestimation problem of scintillation-based profilers. Measured total seeing values are also smaller than the simultaneous measurements, possibly due to the difference in ground layer turbulence between the two sites. The wind profiles show good consistency with the direct measurements by a rawinsonde. Through this study, we establish a method to constrain the free atmospheric profile, the total seeing, and the wind profile by analysing data from a single SH sensor with fine subapertures. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
9. Robust functional ANOVA with application to additive manufacturing.
- Author
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Centofanti, Fabio, Colosimo, Bianca Maria, Grasso, Marco Luigi, Menafoglio, Alessandra, Palumbo, Biagio, and Vantini, Simone
- Subjects
MONTE Carlo method ,PERMUTATIONS ,ANALYSIS of variance ,MANUFACTURING processes ,FUNCTIONAL analysis - Abstract
In this paper, we propose a new robust non-parametric functional analysis of variance method (RoFANOVA) that reduces the weights of outlying curves on the functional analysis of variance. It is implemented through a permutation test based on a test statistic obtained via a functional M-estimator. The performance of the RoFANOVA is demonstrated through an extensive Monte Carlo simulation study, where it is compared with some alternatives already presented in the literature, and a motivating real-case study related to the analysis of spatter ejections in an additive manufacturing process. The RoFANOVA method is implemented in the R package rofanova, available online on CRAN. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
10. Model Fidelity and Child Well-Being in Family Team Conference: The Interaction Effect of Racial Matching and Child Race.
- Author
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Kim, Jangmin, Choi, Mijin, LaBrenz, Catherine A, Harris, Marian S, Boyd, Reiko, and Pierce, Barbara J
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RACISM ,ANALYSIS of variance ,RACIAL inequality ,CHILD welfare ,DESCRIPTIVE statistics ,FAMILY relations - Abstract
Family Team Conference (FTC) has been suggested as a promising practice model to effectively reduce racial disproportionality and disparities in child welfare. However, previous studies have noted ongoing challenges to promoting cultural responsiveness in FTC. This study analysed caseworkers' survey data (n = 736) to explore the role of racial matching between caseworkers and children as an effective practice to strengthen the high fidelity of FTC associated with child well-being. The results of the extended regression model indicate that high FTC fidelity was a necessary condition to improve child well-being. However, racial matching was neither a significant factor of child well-being nor a moderator that strengthened the positive association between FTC fidelity and child well-being. Instead, a follow-up analysis showed that caseworkers' competencies for facilitating FTC were a significant moderator to promote the positive effect of FTC fidelity on the well-being of all children regardless of their race. This paper concludes with research and practice implications to make FTC more culturally responsive to achieve its intended outcomes especially for children of colour. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
11. Laboratory Evaluation of the Particle Size Effect on the Performance of an Elastomeric Half-mask Respirator against Ultrafine Combustion Particles.
- Author
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He, Xinjian, Grinshpun, Sergey A., Reponen, Tiina, Yermakov, Michael, McKay, Roy, Haruta, Hiroki, and Kimura, Kazushi
- Subjects
BREATHING apparatus ,ENVIRONMENTAL exposure prevention ,SMOKE inhalation injuries ,AEROSOLS ,ANALYSIS of variance ,COMMERCIAL product evaluation ,CLINICAL pathology ,EMERGENCY medical technicians ,EXPERIMENTAL design ,FIRE fighters ,HUMAN anatomical models ,INDUSTRIAL hygiene ,NANOPARTICLES ,PARTICLES ,PROBABILITY theory ,RESEARCH funding ,OCCUPATIONAL hazards ,PARTICULATE matter ,DATA analysis software ,DESCRIPTIVE statistics ,PREVENTION - Abstract
Objectives: This study quantified the particle size effect on the performance of elastomeric half-mask respirators, which are widely used by firefighters and first responders exposed to combustion aerosols. Methods: One type of elastomeric half-mask respirator equipped with two P-100 filters was donned on a breathing manikin while challenged with three combustion aerosols (originated by burning wood, paper, and plastic). Testing was conducted with respirators that were fully sealed, partially sealed (nose area only), or unsealed to the face of a breathing manikin to simulate different faceseal leakages. Three cyclic flows with mean inspiratory flow (MIF) rates of 30, 85, and 135L/min were tested for each combination of sealing condition and combustion material. Additional testing was performed with plastic combustion particles at other cyclic and constant flows. Particle penetration was determined by measuring particle number concentrations inside and outside the respirator with size ranges from 20 to 200nm. Results: Breathing flow rate, particle size, and combustion material all had significant effects on the performance of the respirator. For the partially sealed and unsealed respirators, the penetration through the faceseal leakage reached maximum at particle sizes >100nm when challenged with plastic aerosol, whereas no clear peaks were observed for wood and paper aerosols. The particles aerosolized by burning plastic penetrated more readily into the unsealed half-mask than those aerosolized by the combustion of wood and paper. The difference may be attributed to the fact that plastic combustion particles differ from wood and paper particles by physical characteristics such as charge, shape, and density. For the partially sealed respirator, the highest penetration values were obtained at MIF = 85L/min. The unsealed respirator had approximately 10-fold greater penetration than the one partially sealed around the bridge of the nose, which indicates that the nose area was the primary leak site. [ABSTRACT FROM AUTHOR]
- Published
- 2013
12. Multivariate forecasting of road traffic flows in the presence of heteroscedasticity and measurement errors.
- Author
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Anacleto, Osvaldo, Queen, Catriona, and Albers, Casper J.
- Subjects
REGRESSION analysis ,TRAFFIC flow ,TIME series analysis ,MULTIVARIATE analysis ,ANALYSIS of variance ,ACQUISITION of data ,MEASUREMENT errors ,HETEROSCEDASTICITY - Abstract
. Linear multiregression dynamic models, which combine a graphical representation of a multivariate time series with a state space model, have been shown to be a promising class of models for forecasting traffic flow data. Analysis of flows at a busy motorway intersection near Manchester, UK, highlights two important modelling issues: accommodating different levels of traffic variability depending on the time of day and accommodating measurement errors due to data collection errors. This paper extends linear multiregression dynamic models to address these issues. Additionally, the paper investigates how close the approximate forecast limits that are usually used with the linear multiregression dynamic model are to the true, but not so readily available, forecast limits. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
13. Examining smoke-free coalitions in Armenia and Georgia: baseline community capacity.
- Author
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Berg, Carla J, Dekanosidze, Ana, Torosyan, Arevik, Grigoryan, Lilit, Sargsyan, Zhanna, Hayrumyan, Varduhi, Topuridze, Marina, Sturua, Lela, Harutyunyan, Arusyak, Kvachantiradze, Lela, Maglakelidze, Nino, Gamkrelidze, Amiran, Abovyan, Romela, Bazarchyan, Alexander, and Kegler, Michelle C
- Subjects
SMOKING prevention ,ANALYSIS of variance ,CHI-squared test ,COALITIONS ,COMMUNITIES ,HEALTH policy ,PAIRED comparisons (Mathematics) ,RESEARCH funding ,STATISTICAL sampling ,STATISTICS ,SOCIOECONOMIC factors ,RANDOMIZED controlled trials ,TREATMENT effectiveness ,HUMAN services programs ,DATA analysis software ,DESCRIPTIVE statistics ,NON-communicable diseases - Abstract
Local coalitions can advance public health initiative but have not been widely used or well-studied in low- and middle-income countries. This paper provides (i) an overview of an ongoing matched-pairs community-randomized controlled trial in 28 communities in Armenia and Georgia (N = 14/country) testing local coalitions to promote smoke-free policies/enforcement and (ii) characteristics of the communities involved. In July–August 2018, key informants (e.g. local public health center directors) were surveyed to compare their non-communicable disease (NCD) and tobacco-related activities across countries and across condition (intervention/control). More than half of the informants (50.0–57.1%) reported their communities had programs addressing hypertension, diabetes, cancer and human papilloma virus, with 85.7% involving community education and 32.1% patient education programs. Eleven communities (39.3%) addressed tobacco control, all of which were in Georgia. Of those, all included public/community education and the majority (72.7–81.8%) provided cessation counseling/classes, school/youth prevention programs, healthcare provider training or activities addressing smoke-free environments. Informants in Georgia versus Armenia perceived greater support for tobacco control from various sectors (e.g. government, community). No differences were found by condition assignment. This paper provides a foundation for presenting subsequent analyses of this ongoing trial. These analyses indicate wide variability regarding NCD-related activities and support across communities and countries. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
14. The effectiveness of interventions to establish smoke-free homes in pregnancy and in the neonatal period: a systematic review.
- Author
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Baxter, Susan, Blank, Lindsay, Everson-Hock, Emma S., Burrows, Julia, Messina, Josie, GuillaUme, Louise, and Goyder, Elizabeth
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COUNSELING ,PASSIVE smoking ,SMOKING prevention ,ANALYSIS of variance ,PROBABILITY theory ,RESEARCH funding ,SELF-evaluation ,SYSTEMATIC reviews ,HOME environment ,MOTIVATIONAL interviewing ,CHILDREN ,PREGNANCY ,PREVENTION - Abstract
This review considers the effectiveness of interventions to encourage the establishment of smoke-free homes during pregnancy and the neonatal period. A comprehensive search of the literature was undertaken to find relevant studies via electronic databases, citations and reference lists of included studies. The searches identified 17 papers that met the inclusion criteria. These were quality assessed and data extracted. Due to heterogeneity of the papers, a narrative synthesis was completed. Interventions were categorized in terms of those based on counselling, counselling plus additional elements, individually adapted programmes and motivational interviewing. The findings suggest inconclusive evidence relating to these intervention types, with a range of outcome measures reported. There were limitations throughout the papers in terms of study quality (especially sample size) and poor reporting of results in relation to effectiveness. The review was limited by its very specific population; however, it suggests that currently there is mixed evidence for the effectiveness of interventions to reduce parental environmental tobacco smoke in early infancy. [ABSTRACT FROM AUTHOR]
- Published
- 2011
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- View/download PDF
15. Path Dependence in Aggregate Output.
- Author
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Durlauf, Steven N.
- Subjects
ECONOMICS ,INDUSTRIES ,STOCHASTIC analysis ,INDUSTRIAL productivity ,ANALYSIS of variance - Abstract
This paper studies an economy in which incomplete markets and strong complementarities interact to generate path dependent aggregate output fluctuations. An economy is said to be path dependent when the effect of a shock on the level of aggregate output is permanent in the absence of future offsetting shocks. We analyze the evolution of an economy which consists of a countable infinity of industries. The production functions of individual firms in each industry are nonconvex and are linked through localized technological complementarities. The productivity of each firm at t is determined by the production decisions of technologically similar industries at t-1. No markets exist which allow firms and industries to exploit complementarities by coordinating production decisions. This market incompleteness produces several interesting effects on aggregate output behavior. First, multiple stochastic equilibria exist in aggregate activity. These equilibria are distinguished by differences in both the mean and the variance of output. Second, output movements are path dependent as aggregate productivity shocks indefinitely affect real activity by shifting the economy across equilibria. Third, when aggregate shocks are recurrent, the economy cycles between periods of boom and depression. Simulations of example economies illustrate how market incompleteness can produce rich aggregate dynamics. [ABSTRACT FROM AUTHOR]
- Published
- 1994
- Full Text
- View/download PDF
16. Books on Quantitative Methods for Consumer Research.
- Author
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Rao, Vithala R.
- Subjects
QUANTITATIVE research ,PRINCIPAL components analysis ,CONSUMER research ,BOOKS & reading ,FACTOR analysis ,CONSUMER behavior ,MULTIVARIATE analysis ,ANALYSIS of variance ,SPECIAL issues of periodicals ,DATA analysis ,BOOK evaluations - Abstract
This paper presents a systematic review of selected books published during the last five to ten years that deal with quantitative methods. A scheme for organizing various data analysis situations and appropriate techniques is developed as a basis for this review. Some special issues on multivariate methods and opportunities for development of new methods are also discussed. [ABSTRACT FROM AUTHOR]
- Published
- 1980
- Full Text
- View/download PDF
17. new approach to minimize carbon emission rate in turning processes.
- Author
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Cakir, Ali Kemal
- Subjects
CARBON emissions ,NUMERICAL control of machine tools ,TAGUCHI methods ,CUTTING tools ,ANALYSIS of variance - Abstract
This paper aims to analyze the correlation between CNC machine turning properties and the CO
2 output, so that a minimum value is obtained and an optimal process is created. The need to find an optimal process is to help in reducing carbon emissions during the ongoing climate change. In this study, the total carbon emission values in turning have been investigated by calculating the carbon emission values of the features used in turning processes, which are work piece, cutting tool, machine electrical system, cutting tool features, cutting parameters, chip removal, etc. The actions to be taken in experimental study are decided. In the first stage, the equations required to calculate the carbon emission values are determined. Then, carbon emission values were calculated. An experimental design was created in the Taguchi method in order to use the carbon emission values obtained. In the experimental design, the cutting parameters were chosen as the factor, while the cutting time and carbon emission values were chosen as the response. Next, optimum conditions were determined in minimizing the carbon emission value. Later, the most effective cutting parameter with minimum carbon emission value was found in an analysis of variance. Unlike the studies on carbon emission in the machining sector in the literature, the effect of cutting parameters on cutting time and thus on carbon emission was also investigated. Again, in the study, unlike the studies in the literature, a numerical value is given in determining the lowest carbon emission. [ABSTRACT FROM AUTHOR]- Published
- 2021
- Full Text
- View/download PDF
18. Simpler bootstrap estimation of the asymptotic variance of <italic>U</italic>‐statistic‐based estimators.
- Author
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Honoré, Bo E. and Hu, Luojia
- Subjects
STATISTICAL bootstrapping ,ANALYSIS of variance ,SIMULATION methods & models ,INFERENTIAL statistics ,COMPUTATIONAL complexity - Abstract
Summary: The bootstrap is a popular and useful tool for estimating the asymptotic variance of complicated estimators. Ironically, the fact that the estimators are complicated can make the standard bootstrap computationally burdensome because it requires repeated recalculation of the estimator. In this paper, we propose a method that is specific to extremum estimators based on
U ‐statistics. The contribution here is that rather than repeated recalculation of theU ‐statistic‐based estimator, we can recalculate a related estimator based on single sums. A simulation study suggests that the approach leads to a good approximation to the standard bootstrap and that if this is the goal, then our approach is superior to numerical derivative methods. [ABSTRACT FROM AUTHOR]- Published
- 2018
- Full Text
- View/download PDF
19. Wipe Sampling Method and Evaluation of Environmental Variables for Assessing Surface Contamination of 10 Antineoplastic Drugs by Liquid Chromatography/Tandem Mass Spectrometry.
- Author
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Colombo, Manuel, Jeronimo, Matthew, Astrakianakis, George, Apte, Chirag, and Chun-Yip Hon
- Subjects
ANALYSIS of variance ,ANTINEOPLASTIC agents ,ENVIRONMENTAL monitoring ,FLUOROURACIL ,HEALTH facilities ,HIGH performance liquid chromatography ,LIQUID chromatography ,MASS spectrometry ,METHOTREXATE ,PACLITAXEL ,PROBABILITY theory ,RESEARCH evaluation ,RESEARCH funding ,VINBLASTINE ,VINCRISTINE ,WORK environment ,DOCETAXEL ,OCCUPATIONAL hazards ,ENVIRONMENTAL exposure ,OXALIPLATIN ,CYCLOPHOSPHAMIDE ,DATA analysis software ,DESCRIPTIVE statistics ,IFOSFAMIDE - Abstract
This paper describes a novel wipe sampling and high-performance liquid chromatography/tandem mass spectrometry (HPLC-MS/MS) method capable of simultaneously detecting 10 antineoplastic drugs (5-fluorouracil, oxaliplatin, methotrexate, vindesine, ifosfamide, cyclophosphamide, vincristine, vinblastine, docetaxel, and paclitaxel). The good overall recoveries and sensitivity values of this method along with the comparatively short run time (8 min) allows for its use in routine monitoring in health care facilities. The long-term behavior of the studied drugs on contaminated surfaces and the effect of surface roughness on drug recoveries were studied to gain insights about how these environmental variables influence the detection, cleaning, and occupational exposure of these drugs. Surfaces with higher roughness parameter (R
a ) values (rougher) had the lowest recoveries while those with lower Ra (smoother) presented the highest recoveries. Long-term assessments evidence distinctive drug behaviors with oxaliplatin, vindesine, vincristine, and vinblastine being the less persistent drugs (~20% was recovered after 24 h) and docetaxel and paclitaxel the most persistent drugs with recoveries of 40% and 80% after 1 month. This information indicates the importance of collecting ancillary information about drug usage (throughput, timing, cleaning procedures, etc.) to interpret the results in the context of potential exposure. Finally, the method was successfully applied to evaluate trace surface contamination down to the single picogram per square centimeter in multiple work areas within three local health care centers on Vancouver Island, Canada. [ABSTRACT FROM AUTHOR]- Published
- 2017
- Full Text
- View/download PDF
20. Realized Skewness.
- Author
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Neuberger, Anthony
- Subjects
MOMENTS method (Statistics) ,RATE of return on stocks ,RATE of return ,MATHEMATICAL models of finance ,MATHEMATICAL models ,STOCK prices ,ANALYSIS of variance - Abstract
The third moment of returns is important for asset pricing, but it is hard to measure precisely, particularly at long horizons. This paper proposes a definition of the realized third moment that is computed from high-frequency returns. It provides an unbiased estimate of the true third moment of long-horizon returns, doing for the third moment what realized variance does for the second moment. The methodology is used to demonstrate that the skewness of equity index returns, far from diminishing with horizon, actually increases with horizons up to a year, and its magnitude is economically important. [ABSTRACT FROM AUTHOR]
- Published
- 2012
- Full Text
- View/download PDF
21. Categorizing h-index variants.
- Author
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Schreiber, M., Malesios, C. C., and Psarakis, S.
- Subjects
H-index (Citation analysis) ,ANALYSIS of variance ,FACTOR analysis ,INFORMATION resources ,LOGARITHMS ,CITATION analysis ,ELECTRONIC data processing documentation ,DATA transmission systems - Abstract
Utilizing the Hirsch index h and some of its variants for an exploratory factor analysis we discuss whether one of the most important Hirsch-type indices, namely the g-index, comprises information about not only the size of the productive core but also the impact of the papers in the core. We also study the effect of logarithmic and square-root transformation of the data utilized in the factor analysis. To demonstrate our approach we use a real data example analysing the citation records of 26 physicists compiled from the Web of Science. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
- View/download PDF
22. The association between students’ perceptions of a caring teacher and sexual initiation. A study among South African high school students.
- Author
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Helleve, Arnfinn, Flisher, Alan J., Onya, Hans, Mathews, Catherine, Aarø, Leif Edvard, and Klepp, Knut-Inge
- Subjects
ANALYSIS of variance ,CARING ,CONFIDENCE intervals ,EPIDEMIOLOGY ,PSYCHOLOGY of high school students ,LONGITUDINAL method ,PROBABILITY theory ,RESEARCH funding ,SELF-evaluation ,HUMAN sexuality ,STATISTICS ,SURVEYS ,T-test (Statistics) ,TEACHER-student relationships ,LOGISTIC regression analysis ,DATA analysis ,DATA analysis software ,ADOLESCENCE - Abstract
This paper has the following aims: (i) to explore the extent to which students who received an intervention involving HIV/AIDS and sexuality perceived that their teacher cared for their health and well-being, (ii) to investigate the characteristics of students who reported to have caring teachers and (iii) to document the association between students’ perceptions of care and reported onset of sexual activity. Data were obtained from the second follow-up survey of a prospective study carried out among high school students in South Africa (Cape Town and Mankweng). We analyzed data from 3483 students who met the inclusion criteria. Students from the intervention group perceived greater care from teachers than students in the control group. Female students and students from Cape Town perceived having received more care, and their perception of care was associated with the number of lessons received, how often students expressed their opinions in class and how often teachers talked about HIV/AIDS, condoms and abstinence. Students who perceived that their teacher cared for their health and well-being were less likely to initiate sexual intercourse. This is the first paper to demonstrate the salience of the concept of care in studies of school-based HIV/AIDS prevention programs in sub-Saharan Africa. [ABSTRACT FROM PUBLISHER]
- Published
- 2011
- Full Text
- View/download PDF
23. Secular trends and smoke-free policy development in rural Kentucky.
- Author
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Fallin, Amanda, Parker, Lindsay, Lindgreen, Janine, Riker, Carol, Kercsmar, Sarah, and Hahn, Ellen J.
- Subjects
MASS media criticism ,PASSIVE smoking ,SMOKING prevention ,ANALYSIS of variance ,RESEARCH funding ,GOVERNMENT policy ,RANDOMIZED controlled trials ,PREVENTION - Abstract
Secondhand smoke (SHS) exposure causes cardiovascular disease, lung cancer and pulmonary disorders. Smoke-free policies are the most effective way to prevent exposure to SHS. A 5-year community-based randomized control trial (RCT) is in progress to assess factors associated with smoke-free policy development in rural communities. Considering secular trends is critical when conducting community-based RCTs as they may threaten the internal validity of the study. For the purposes of this paper, secular trends are defined as patterns or recurring events that are not directly related to smoke-free policy but have the potential to influence policy development. There are no established protocols to monitor secular trends in the study of smoke-free policy in rural communities. The purpose of this paper is to (i) describe the development of a protocol to identify and monitor secular trends that may threaten the internal validity of a community-based RCT to promote smoke-free policy development and (ii) describe secular trends identified in the first 2 years of the RCT. The sample includes 854 secular events captured from media outlets covering the 40 study counties over the first 2 years of the RCT. Of these 854 events, there were 281 secular events in Year 1 and 573 in Year 2. This paper focuses on five specific categories: ‘tobacco use and cessation activities’, ‘farming’, ‘economics’, ‘city/county infrastructure’ and ‘wellness’. This protocol is a feasible yet time-intensive method of identifying events that may threaten the internal validity of a community-based RCT. [ABSTRACT FROM PUBLISHER]
- Published
- 2011
- Full Text
- View/download PDF
24. A Latent Factor Model of Multivariate Conditional Heteroscedasticity.
- Author
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AGUILAR, MIKE
- Subjects
HETEROSCEDASTICITY ,MULTIVARIATE analysis ,STOCHASTIC analysis ,ECONOMETRICS ,ANALYSIS of variance - Abstract
This paper examines the joint dynamics of a system of asset returns by describing and implementing a factor multivariate stochastic volatility (factor MSV) model. The foundation for the model discussed here is the work of Doz and Renault (2006). Despite its attractive design, that model has not been adopted widely in the literature, most likely due to the difficulty encountered in its implementation. The main contribution of this paper is to illustrate that this factor MSV model can be implemented easily and with only a few modifications. Specifically, I develop a sequential testing procedure that can account simultaneously for a series of nested hypotheses and structure properly the moment conditions used for estimation. A simulation study suggests that the factor MSV model and estimation strategy presented here is able to recover accurately the number of, and dynamics for, the latent factors that drive the conditional volatility of returns. [ABSTRACT FROM PUBLISHER]
- Published
- 2009
- Full Text
- View/download PDF
25. A functional generalized F‐test for signal detection with applications to event‐related potentials significance analysis.
- Author
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Causeur, David, Sheu, Ching‐Fan, Perthame, Emeline, and Rufini, Flavia
- Subjects
SIGNAL detection ,EVOKED potentials (Electrophysiology) ,FUNCTIONAL analysis ,GLOBAL analysis (Mathematics) ,ASYMPTOTIC distribution ,STOCHASTIC processes ,ANALYSIS of variance ,STATISTICAL correlation - Abstract
Motivated by the analysis of complex dependent functional data such as event‐related brain potentials (ERP), this paper considers a time‐varying coefficient multivariate regression model with fixed‐time covariates for testing global hypotheses about population mean curves. Based on a reduced‐rank modeling of the time correlation of the stochastic process of pointwise test statistics, a functional generalized F‐test is proposed and its asymptotic null distribution is derived. Our analytical results show that the proposed test is more powerful than functional analysis of variance testing methods and competing signal detection procedures for dependent data. Simulation studies confirm such power gain for data with patterns of dependence similar to those observed in ERPs. The new testing procedure is illustrated with an analysis of the ERP data from a study of neural correlates of impulse control. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
26. ESTIMATION OF UNCERTAINTY IN MEASUREMENT OF DOSE EQUIVALENT AT LABORATORY LEVEL USING CASO4 :Dy-BASED TLD BADGE SYSTEM IN INDIA.
- Author
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Pradhan, S M, Datta, D, Pathan, Munir S, Srivastava, Kshama, and Selvam, T Palani
- Subjects
UNCERTAINTY ,ANALYSIS of variance ,BADGES ,LABORATORIES ,MEASUREMENT - Abstract
The objective of this paper is to estimate the combined uncertainty in the measurement of dose equivalent at laboratory level using CaSO
4 :Dy-based thermoluminescent dosemeter badge system by including variations in the components of the system. The variability of performance of the system is analysed using random effects one way analysis of variance model. The model enables estimation of the overall variance of the performance of the sampled population. The population in the study comprises all possible indicated dose equivalents on irradiation of dosemeters to a specific dose equivalent and radiation quality. Coefficient of variation and combined uncertainty at 95% level of confidence in the measurement of H p(10) due to S-Cs radiation quality are found to be 6.6 and 14.3%, respectively, at the dose level of 5.31 mSv. The above parameters in the measurement of in-use quantity, i.e. whole body dose or photon dose equivalent are found to be 7.4 and 16.4%, respectively. The performance of the monitoring system on relative response has been observed to be satisfactory. Various factors affecting the variability of performance of the system are identified for further improvement in coefficient of variation. [ABSTRACT FROM AUTHOR]- Published
- 2020
- Full Text
- View/download PDF
27. Critical values for linearity tests in time-varying smooth transition autoregressive models when data are highly persistent.
- Author
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Sandberg, Rickard
- Subjects
ECONOMETRICS ,RANDOM walks ,ASYMPTOTIC distribution ,ARCH model (Econometrics) ,CHI-squared test ,ANALYSIS of variance ,UNITS of time - Abstract
In this paper, we derive asymptotic distributions for linearity tests in time-varying smooth transition autoregressive models in the presence of a unit root. The limiting distributions are non-standard because of the unit root assumption, and it is shown that the linearity hypothesis is rejected far too often (up to 30.9% of the times at a 5% significance level) when using critical values from a chi-square distribution. [ABSTRACT FROM AUTHOR]
- Published
- 2008
- Full Text
- View/download PDF
28. Estimating the intensity of conflict in Iraq.
- Author
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Nason, Guy P. and Bailey, Daniel
- Subjects
INTEGRAL transforms ,ANALYSIS of variance ,IRAQ War, 2003-2011 ,BATTLE casualties ,TIME series analysis ,PROBABILITY theory - Abstract
Since 2003 several Web sites have appeared that track the number of deaths of coalition personnel in the current Iraq conflict. The paper proposes the use of a recently developed multiscale variance stabilization method (the data-driven Haar–Fisz transform) to obtain good estimates of the mean intensity of deaths and demonstrates its statistical advantages over both the running mean (which is currently used on some Web sites) and also the Box–Cox transformation. The paper analyses both the number of deaths due to all causes and also due to hostile actions between June 2003 and March 2006. In both cases it appears that the marginal variance of both time series is an increasing function of the marginal mean. Further, although our estimates exhibit peaks that are related to local increases in intensity of conflict there appears to be a clear underlying increase in intensity of conflict during the conflict but with a decline and levelling off since June 2005. The paper also proposes a tentative inverse relationship between deaths due to non-hostile actions and deaths due to hostile actions. [ABSTRACT FROM AUTHOR]
- Published
- 2008
- Full Text
- View/download PDF
29. Modifying a central composite design to model the process mean and variance when there are hard-to-change factors.
- Author
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Kowalski, Scott M., Vining, G. Geoffrey, Montgomery, Douglas C., and Borror, Connie M.
- Subjects
INDUSTRIAL statistics ,STATISTICS ,ANALYSIS of variance ,MATHEMATICAL models ,SILICON ,MANUFACTURING processes - Abstract
An important question within industrial statistics is how to find operating conditions that achieve some goal for the mean of a characteristic of interest while simultaneously minimizing the characteristic's process variance. Often, people refer to this kind of situation as the robust parameter design problem. The robust parameter design literature is rich with ways to create separate models for the mean and variance from this type of experiment. Many times time and/or cost constraints force certain factors of interest to be much more difficult to change than others. An appropriate approach to such an experiment restricts the randomization, which leads to a split-plot structure. The paper modifies the central composite design to allow the estimation of separate models for the characteristic's mean and variances under a split-plot structure. The paper goes on to discuss an appropriate analysis of the experimental results. It illustrates the methodology with an industrial experiment involving a chemical vapour deposition process for the manufacture of silicon wafers. The methodology was used to achieve a silicon layer thickness value of 485 Å while minimizing the process variation. [ABSTRACT FROM AUTHOR]
- Published
- 2006
- Full Text
- View/download PDF
30. Further results on optimal critical values of pre-test when estimating the regression error variance.
- Author
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Wan, Alan T. K., Guohua Zou, and Ohtani, Kazuhiro
- Subjects
REGRESSION analysis ,ERRORS ,ANALYSIS of variance ,ESTIMATION theory ,ECONOMETRICS - Abstract
This paper enlarges on results of Wan and Zou [Journal of Econometrics 114 (2003), 165–96] on the choice of critical values for pre-test procedures based on the minimum risk criterion. We consider a modification of the general theorem given in Wan and Zou (2003) to obtain the optimal critical value that minimizes the risks of various inequality pre-test estimators of the regression error variance under a general class of first-order differentiable loss functions. Theoretical proofs of earlier numerical results are provided. This paper also presents results on the optimal pre-test critical values for the simultaneous estimation of the error variance and coefficient vector. [ABSTRACT FROM AUTHOR]
- Published
- 2006
- Full Text
- View/download PDF
31. Effects of home care and e-mobile training/consultancy on women's postpartum symptoms and breastfeeding self-efficacy: a randomized clinical trial.
- Author
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Yıkar, Seda Karaçay and Nazik, Evşen
- Subjects
BREASTFEEDING ,HOME care services ,PATIENT education ,MOBILE apps ,REPEATED measures design ,SELF-efficacy ,DATA analysis ,RESEARCH funding ,MOTHERS ,PUERPERIUM ,PILOT projects ,KRUSKAL-Wallis Test ,RANDOMIZED controlled trials ,DESCRIPTIVE statistics ,CHI-squared test ,TELEMEDICINE ,ANALYSIS of variance ,STATISTICS ,COMPUTER assisted instruction ,DATA analysis software ,MEDICAL referrals - Abstract
Background Most women experience breastfeeding problems and need changes due to postpartum physical symptoms and low breastfeeding self-efficacy. Methods Postpartum home care and e-mobile training/consultancy has been introduced to address this issue. This study was conducted as a randomized controlled interventional study. The sample of the study consisted of 75 (home care group = 25, control group = 25, e-mobile training/consultancy group = 25) women who met the sample selection criteria, agreed to participate in the study, and were hospitalized in the postpartum ward of a City Hospital. Data were collected through the Personal Information Form, the Postpartum Physical Symptom Severity Scale and the Breastfeeding Self-Efficacy Scale (BSES). Results In all postpartum stages, a statistically significant difference was detected between the home care, e-mobile training/consultancy and control group women in terms of the Postpartum Physical Symptoms Severity Scale and BSES total mean scores (P < .05). Interviews showed that the home care group had the lowest Postpartum Physical Symptom Severity Scale total mean scores and the highest BSES total mean scores (P < .05). Postpartum home visits and e-mobile training/consultancy should be considered a routine part of postpartum care. It is effective in reducing postpartum physical symptoms and increasing breastfeeding self-efficacy. Conclusıon In line with the results of this study, the use of home care and e-mobile training/consultancy is recommended to decrease physical symptoms and increase breastfeeding self-efficacy. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
32. Widespread Pressure Pain Hyperalgesia Is Not Associated With Morphological Changes of the Wrist Extensor Tendon in Unilateral Lateral Epicondylalgia: A Case–Control Study.
- Author
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Cancela-Cilleruelo, Ignacio, Rodríguez-Jiménez, Jorge, Fernández-de-las-Peñas, César, Cleland, Joshua A, and Arias-Buría, José L
- Subjects
WRIST ,PAIN measurement ,TENNIS elbow ,CROSS-sectional method ,SELF-evaluation ,PEARSON correlation (Statistics) ,SKELETAL muscle ,PRESSURE ,DATA analysis ,QUESTIONNAIRES ,PROBABILITY theory ,PAIN threshold ,NOCICEPTIVE pain ,DESCRIPTIVE statistics ,TENDONS ,HYPERALGESIA ,CASE-control method ,ANALYSIS of variance ,STATISTICS ,CONFIDENCE intervals ,DATA analysis software - Abstract
Objective The aims of the current study were to investigate the presence of widespread pressure hyperalgesia, the presence of structural changes in the wrist extensor tendon and muscle, and their association in people with lateral epicondylalgia (LE). Methods Thirty-seven patients with LE (43% women; mean age = 45.5 [SD = 9.5] years) and 37 controls matched for age and sex and free of pain participated in this study. Pressure pain thresholds (PPTs) were assessed bilaterally over the symptomatic area (elbow), 2 segment-related areas (C5–C6 joint, second intermetacarpal space), and 1 remote area (tibialis anterior) in a blinded design. Ultrasound measurements (eg, cross-sectional area, thickness, and width) of the common wrist extensor tendon and extensor carpi radialis brevis muscle as well as the thickness of the supinator muscle were assessed. Results Patients with LE exhibited lower PPTs bilaterally at all points and lower PPTs at the lateral epicondyle and second intermetacarpal space on the symptomatic side as compared to the nonsymptomatic side (η
2 from 0.123–0.369; large effects). Patients exhibited higher cross-sectional area and width of the common wrist extensor tendon (η2 from 0.268–0.311; large effects) than controls bilaterally, whereas tendon thickness was also higher (η2 = 0.039; small effects) on the painful side than on the nonpainful side. Conclusions This study reported bilateral widespread pressure pain hyperalgesia and morphological changes in the tendon, but not the muscle, in LE. Pressure pain sensitivity and morphological changes were not associated in individuals with LE. Impact Management of LE should consider altered nociceptive pain processing and structural tendon changes as 2 different phenomena in patients with LE. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
33. Does Computer Use Improve Older Adults' Cognitive Functioning? Evidence From the Personal Reminder Information and Social Management Trial.
- Author
-
Zhang, Shenghao, Boot, Walter R, and Charness, Neil
- Subjects
- *
COMPUTERS , *ANALYSIS of variance , *COGNITIVE aging , *PRE-tests & post-tests , *INDEPENDENT living , *COGNITIVE testing , *TECHNOLOGY , *STATISTICAL sampling - Abstract
Background and Objectives Numerous longitudinal studies suggest that technology use in late adulthood is associated with cognitive benefits. Using data from a randomized controlled trial, the current study examined whether computer use improves cognition in older adults with little to no previous computer experience. Research Design and Methods This study used data from the Personal Reminder Information and Social Management (PRISM) trial. Community-dwelling older adults with little previous computer experience (M Age = 76.15) were randomly assigned to learn and use a computer (the PRISM system, n = 150) or interact with parallel content delivered in a nondigital format (paper binder, n = 150) for 12 months. Objective and subjective cognitive outcomes were measured before (pretest) and after the intervention (posttest). Latent change score models and Bayesian analysis of variances were used to examine cognitive change at the ability and individual measure level. Results Computer training and use for 12 months did not lead to cognitive improvements at the ability level. Strong evidence against cognitive benefits at the individual measure level was also observed. Discussion and Implications Casual computer use does not provide enough cognitive stimulation to improve cognition in late adulthood. Cognitive benefits observed in longitudinal studies may be mediated by other factors or influenced by confounding variables. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
34. HEIA tools: inclusion of migrants in health policy in Canada.
- Author
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Pottie, Kevin, Agic, Branka, Archibald, Douglas, Ratnayake, Ayesha, Tapia, Marcela, and Thanos, Joanne
- Subjects
HEALTH policy ,ANALYSIS of variance ,DECISION making ,INTERVIEWING ,RESEARCH methodology ,MIGRANT labor ,NOMADS ,QUESTIONNAIRES ,SCALE analysis (Psychology) ,SELF-evaluation ,STATISTICAL hypothesis testing ,STATISTICS ,WORLD health ,INFORMATION resources ,QUALITATIVE research ,DATA analysis ,QUANTITATIVE research ,HUMAN services programs ,PRE-tests & post-tests ,RETROSPECTIVE studies ,HEALTH & social status ,DESCRIPTIVE statistics - Abstract
This paper introduces the Migrant Populations Equity Extension for Ontario's Health Equity Impact Assessment (HEIA) initiatives. It provides a mechanism to address the needs of migrant populations, within a program and policy framework. Validation of an equity extension framework using community leaders and health practitioners engaged in HEIA workshops across Ontario. Participants assessed migrants' health needs and discussed how to integrate these needs into health policy. The Migrant Populations Equity Extension's framework assists decision makers assess relevant populations, collaborate with immigrant communities, improve policy development and mitigate unintended negative impacts of policy initiatives. The tool framework aims to build stakeholder capacity and improve their ability to conduct HEIAs while including migrant populations. The workshops engaged participants in equity discussions, enhanced their knowledge of migrant policy development and promoted HEIA tools in health decision-making. Prior to these workshops, many participants were unaware of the HEIA tool. The workshops informed the validation of the equity extension and support materials for training staff in government and public health. Ongoing research on policy implementation would be valuable. Public health practitioners and migrant communities can use the equity extension's framework to support decision-making processes and address health inequities. This framework may improve policy development and reduce health inequities for Ontario's diverse migrant populations. Many countries are now using health impact assessment and health equity frameworks. This migration population equity extension is an internationally unique framework that engages migrant communities. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
35. Poverty-related diseases: factors that predict coping in two Cameroonian settings.
- Author
-
Makoge, Valerie, Hogeling, Lette, Maat, Harro, Vaandrager, Lenneke, and Koelen, Maria
- Subjects
POVERTY areas ,PSYCHOLOGICAL adaptation ,AGRICULTURE ,ANALYSIS of variance ,BLUE collar workers ,CHI-squared test ,COLLEGE students ,STATISTICAL correlation ,DISEASES ,ECOLOGY ,FACTOR analysis ,HEALTH status indicators ,QUESTIONNAIRES ,RESEARCH evaluation ,SCALE analysis (Psychology) ,SELF-efficacy ,STATISTICS ,STRESS management ,MULTIPLE regression analysis ,SOCIOECONOMIC factors ,WELL-being ,DATA analysis software ,DESCRIPTIVE statistics - Abstract
In this paper, we explore the connection between poverty and health (poverty-related diseases: PRDs) by investigating the factors that play a role in how two groups of people in Cameroon cope with health challenges: workers in a large agro-industrial organization (living in 'camps') and students in two major universities (living on 'campuses'). We investigated factors reported in the literature as being associated with coping, summarized under the 'salutogenic umbrella', as well as demographic, social and environmental factors. A total of 509 respondents from camps and campuses participated in this study. We used a combination of standardized and un-standardized survey instruments to measure coping. We used χ
2 and ANOVA tests to investigate bivariate differences and multiple logistic regression analysis to determine which significant survey factors predicted coping. Our results showed expected and unexpected differences between the settings. Individual dispositional factors such as sense of coherence (SOC), self-efficacy (SE), subjective wellbeing and self-rated health differed significantly between the settings. Expected coping resources such as income and SE did not differ between non-copers and copers. Two factors emerged as predictors of coping: living environment (setting) and SOC. Our results highlight the need for a multidimensional perspective on poverty and also the need to apply the salutogenic approach in PRD research. In particular, the emphasis this approach puts on stressors and the capacity to employ a variety of resources to overcome stressors is a fruitful way to better understand PRDs and the importance of location-specific circumstances where poverty, health and diseases are connected. [ABSTRACT FROM AUTHOR]- Published
- 2019
- Full Text
- View/download PDF
36. Quantifier Variance, Ontological Pluralism and Ideal Languages.
- Author
-
Javier-Castellanos, A Arturo
- Subjects
PLURALISM ,NATURALNESS (Linguistics) ,ANALYSIS of variance ,PHILOSOPHY - Abstract
Kris McDaniel has recently defended a criterion for being an ontological pluralist that classifies the quantifier variantist as one. In this paper, I argue that this is a mistake. There is an important difference between the two views, which is sometimes obscured by a common view in the metaphysics of fundamentality. According to the simple analysis, a language is ideal—it allows for a maximally metaphysically perspicuous description of reality—just in case all its primitives are perfectly natural. I argue that this analysis struggles to distinguish quantifier variance from ontological pluralism, and then I discuss various accounts that can do better. I then propose a criterion for being an ontological pluralist that does not misclassify the quantifier variantist. Finally, I discuss some additional advantages of my proposal. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
37. Scientific Style and the Conduct of Consumer Research.
- Author
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Hirschman, Elizabeth C.
- Subjects
CONSUMER research ,INQUIRY (Theory of knowledge) ,COMPREHENSION ,METHODOLOGY ,EMPIRICAL research ,PSYCHOLOGICAL typologies ,HUMANISTIC psychology ,ANALYSIS of variance ,HUMANISM ,EMPIRICISM ,PHILOSOPHICAL analysis ,CONCEPTUALISM - Abstract
This paper describes four styles of conducting scientific inquiry--analytical science, conceptual theory, conceptual humanism, and particular humanism. The work of four consumer researchers--James Bettman, Russell Belk, Morris Holbrook, and Sidney Levy--is used to explicate each approach to inquiry. The author argues for a broader based perspective of the scientific enterprise and for mutual acceptance of different ways of conducting research. [ABSTRACT FROM AUTHOR]
- Published
- 1985
- Full Text
- View/download PDF
38. The Interaction of Advertising and Evidence.
- Author
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Deighton, John
- Subjects
ADVERTISING ,DECISION theory ,MANAGEMENT science ,BEHAVIORAL assessment ,DECISION making ,BEHAVIORAL research ,COGNITIVE dissonance ,ANALYSIS of variance ,EXPECTANCY theories ,ADVERTISING effectiveness - Abstract
Recent advertising research appears to neglect the role of evidence in persuasion. From work on confirmatory bias in the field of behavioral decision theory, this paper argues for an interaction between advertising and evidence on evaluations, and finds experimental support for the interaction. Implications are drawn for advertising testing and for hierarchy models of advertising effects. [ABSTRACT FROM AUTHOR]
- Published
- 1984
- Full Text
- View/download PDF
39. Consumer Choice Strategies for Comparing Noncomparable Alternatives.
- Author
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Johnson, Michael D.
- Subjects
CONSUMER preferences ,BRAND name products ,CHOICE (Psychology) ,DECISION making ,PRODUCT attributes ,CONJOINT analysis ,METHODOLOGY ,ANALYSIS of variance ,CONSUMER research ,CONSUMER behavior - Abstract
Research on consumer choice has focused on easily comparable alternatives, a subset of the choices consumers regularly face. This paper outlines the problem and two general strategies for comparing noncomparable alternatives, a subset of choices that has been overlooked in the literature. Experiments are reported that support use of the strategies. [ABSTRACT FROM AUTHOR]
- Published
- 1984
- Full Text
- View/download PDF
40. Lack of Identification in Semiparametric Instrumental Variable Models With Binary Outcomes.
- Author
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Burgess, Stephen, Granell, Raquel, Palmer, Tom M., Sterne, Jonathan A. C., and Didelez, Vanessa
- Subjects
STATISTICS methodology ,DATA analysis ,EPIDEMIOLOGY research methodology ,AGE factors in disease ,ANALYSIS of variance ,ATTRIBUTION (Social psychology) ,COMPUTER simulation ,CONCEPTUAL structures ,MENARCHE ,RESEARCH ,BODY mass index ,RESEARCH methodology evaluation - Abstract
A parameter in a statistical model is identified if its value can be uniquely determined from the distribution of the observable data. We consider the context of an instrumental variable analysis with a binary outcome for estimating a causal risk ratio. The semiparametric generalized method of moments and structural mean model frameworks use estimating equations for parameter estimation. In this paper, we demonstrate that lack of identification can occur in either of these frameworks, especially if the instrument is weak. In particular, the estimating equations may have no solution or multiple solutions. We investigate the relationship between the strength of the instrument and the proportion of simulated data sets for which there is a unique solution of the estimating equations. We see that this proportion does not appear to depend greatly on the sample size, particularly for weak instruments (p² ≤ 0.01). Poor identification was observed in a considerable proportion of simulated data sets for instruments explaining up to 10% of the variance in the exposure with sample sizes up to 1 million. In an applied example considering the causal effect of body mass index (weight (kg)/height (m)²) on the probability of early menarche, estimates and standard errors from an automated optimization routine were misleading. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
41. Variance estimation in the particle filter.
- Author
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Lee, A and Whiteley, N
- Subjects
ANALYSIS of variance ,LEAST squares ,ESTIMATION theory ,STOCHASTIC processes ,MATHEMATICAL statistics ,PROBABILITY theory - Abstract
This paper concerns numerical assessment of Monte Carlo error in particle filters. We show that by keeping track of certain key features of the genealogical structure arising from resampling operations, it is possible to estimate variances of a number of Monte Carlo approximations that particle filters deliver. All our estimators can be computed from a single run of a particle filter. We establish that, as the number of particles grows, our estimators are weakly consistent for asymptotic variances of the Monte Carlo approximations and some of them are also non-asymptotically unbiased. The asymptotic variances can be decomposed into terms corresponding to each time step of the algorithm, and we show how to estimate each of these terms consistently. When the number of particles may vary over time, this allows approximation of the asymptotically optimal allocation of particle numbers. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
42. A conditional composite likelihood ratio test with boundary constraints.
- Author
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Chen, Yong, Huang, Jing, Ning, Yang, Liang, Kung-Yee, and Lindsay, Bruce G
- Subjects
LIKELIHOOD ratio tests ,DEGREES of freedom ,ANALYSIS of variance ,RATIO & proportion ,SIMULATION methods & models - Abstract
Composite likelihood has been widely used in applications. The asymptotic distribution of the composite likelihood ratio statistic at the boundary of the parameter space is a complicated mixture of weighted χ
2 distributions. In this paper we propose a conditional test with data-dependent degrees of freedom. We consider a modification of the composite likelihood which satisfies the second-order Bartlett identity.We show that the modified composite likelihood ratio statistic given the number of estimated parameters lying on the boundary converges to a simple χ2 distribution. This conditional testing procedure is validated through simulation studies. [ABSTRACT FROM AUTHOR]- Published
- 2018
- Full Text
- View/download PDF
43. Self-Efficacy and Outcomes: Validating a Measure Comparing Social Work Students' Perceived and Assessed Ability in Core Pre-Placement Skills.
- Author
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Tompsett, Hilary, Henderson, Kathleen, Mathew Byrne, Jane, Gaskell Mew, Elaine, and Tompsett, Chris
- Subjects
SOCIAL workers ,ABILITY ,ANALYSIS of variance ,CONFIDENCE ,STATISTICAL correlation ,FACTOR analysis ,INTERVIEWING ,QUESTIONNAIRES ,RESEARCH evaluation ,SELF-efficacy ,STUDENTS ,STUDENT attitudes ,TRAINING ,JOB performance ,EDUCATIONAL outcomes ,NATIONAL competency-based educational tests ,PSYCHOLOGY - Abstract
Assessing and researching social work students' skills prior to first placement presents challenges, but also the opportunity for comparison with students' perceptions of their abilities/skills at an important professional development stage. This paper reports on initial quantitative results from a three-year study of students' self-confidence in core skills/micro skills at the profession's 'Readiness for Direct Practice' threshold in England. A combined cohort of postgraduate and undergraduate social work students (n = 95) at one university completed a three-stage integrated self/module-evaluation questionnaire during a common module. Using a Self-Assessed Skills Inventory (SASI), a self-efficacy scale based on Likert-scale responses to twenty-eight statements was developed and validated for internal consistency. Linear analysis of self-efficacy values, assessment outcome, programme level and prior work experience for a non-biased sample (n = 66) at the final stage shows results are independent of both programme level and prior experience. However, a correlation established between self-efficacy and marks for an assessed interview is shown to be strongly positive and significantly predictive for undergraduates, but weaker and negative for postgraduates. Considering relevant literature, the study's limitations and implications for other social work programmes, this study establishes direct criterion-related validity between a self-efficacy scale and formal assessment. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
44. Causal Prediction of Top-k Event Types Over Real-Time Event Streams.
- Author
-
SAURAV ACHARYA, LEE, BYUNG SUK, and HINES, PAUL
- Subjects
REAL-time control ,CAUSAL models ,BIG data ,MATHEMATICAL statistics ,ANALYSIS of variance - Abstract
This paper addresses the problem of causally predicting the top-k most likely next events over real-time event streams. Existing approaches have limitations--(i) they model causality in an acyclic causal network structure and search it to find the top-k next events, which does not work with real world event streams as they frequently manifest cyclic causality, and (ii) they prune out possible non-causal links from a causal network too aggressively and end up omitting many less frequent yet important causal links. We overcome these limitations using a novel event precedence model (EPM) and a run-time causal inference mechanism. The EPM constructs a Markov chain incrementally over event streams, where an edge between two events signifies a temporal precedence relationship between them, which is a necessary condition for causality. Then, the run-time causal inference mechanism performs causality tests on the EPM during query processing, and temporal precedence relationships that fail the causality test in the presence of other events are removed. Two query processing algorithms are presented. One performs exhaustive search on the model and the other performs more efficient reduced search with early termination. Experiments using two real data sets (cascading blackouts in power systems and web page views) verify efficacy and efficiency of the proposed probabilistic top-k prediction algorithms. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
45. Exploring Symptom Responses to Upper Limb Neural Test Variations of the Radial Nerve in Patients With Lateral Epicondylalgia: An Observational Study.
- Author
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Albert-Lucena, Daniel, Navarro-Santana, Marcos José, Días-Arribas, María José, Valera-Calero, Juan Antonio, Fernández-de-las-Peñas, César, and Plaza-Manzano, Gustavo
- Subjects
TENNIS elbow ,NEUROLOGIC examination ,PAIN measurement ,RADIAL nerve ,ARM ,DISEASE duration ,DATA analysis ,T-test (Statistics) ,SCIENTIFIC observation ,QUESTIONNAIRES ,VISUAL analog scale ,DESCRIPTIVE statistics ,CHI-squared test ,MANN Whitney U Test ,ONE-way analysis of variance ,FRIEDMAN test (Statistics) ,ANALYSIS of variance ,STATISTICS ,SUPINATION ,PARESTHESIA ,EXERCISE tests ,DATA analysis software ,PATIENT positioning ,GRIP strength ,MUSCLE contraction ,SYMPTOMS - Abstract
Objective. Clinical practice guidelines recommend the radial nerve mechanosensitivity evaluation in patients with lateral epicondylalgia. Despite different positions and sequences having been described, no research analyzed how each variation triggers symptoms associated with lateral epicondylalgia. The aim of this study was to explore the effects of different positions and sequences in the upper limb neural tension test 2b (ULNT2b) in symptom responses in patients with lateral epicondylalgia. Methods. In this observational study, 66 patients underwent 4 test conditions: standard ULNT2b, ULNT2b proximal to distal, ULNT2B with resisted supination, and resisted supination isolated. Paresthesia sensations, symptom reproduction, pain intensity (measured using a visual analog scale), and distribution of painful symptoms data were collected. Results. Significant differences in paresthesia sensations were observed between groups, with significant differences between the standard ULNT2B and other ULNT variations or resisted supination maneuvers. Symptom reproduction also differed significantly across groups, with significant differences between the standard ULNT2B and other ULNT or resisted supination tests. The positive/negative test and percentage of distribution of painful symptoms scores varied significantly across 4 conditions in both lateral and frontal views. Although pain intensity scores during tests were comparable among the tests, distribution of painful symptoms differed significantly. Conclusion. Variations in the ULNT2b test can affect symptom responses in patients with lateral epicondylalgia. The standard ULNT2b test appears more effective at reproducing symptoms, intensity of paresthesia, and distribution of painful symptoms compared to other ULNT variations and the resisted supination test. Impact. ULNT2b sequences have been shown to elicit varying responses concerning paresthesia, replication of familiar symptoms, positive/negative test results, and distribution of painful symptoms. Clinicians should consider specific test variations during the patients' radial nerve mechanosensitivity assessment to identify aggravating factors reproducing recognizable symptoms. A control group of asymptomatic participants and the role of presence of other comorbidities, psychological factors, or the duration of symptoms were not considered in this study and might play an important role influencing the results of the tests. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
46. Aggregate-data estimation of an individual patient data linear random effects meta-analysis with a patient covariate-treatment interaction term.
- Author
-
Kovalchik, Stephanie A.
- Subjects
DATA analysis ,ESTIMATION theory ,META-analysis ,LINEAR statistical models ,MEDICAL care ,ANALYSIS of variance - Abstract
Individual patient-data meta-analysis of randomized controlled trials is the gold standard for investigating how patient factors modify the effectiveness of treatment. Because participant data from primary studies might not be available, reliable alternatives using published data are needed. In this paper, I show that the maximum likelihood estimates of a participant-level linear random effects meta-analysis with a patient covariate-treatment interaction can be determined exactly from aggregate data when the model's variance components are known. I provide an equivalent aggregate-data EM algorithm and supporting software with the R package ipdmeta for the estimation of the “interaction meta-analysis” when the variance components are unknown. The properties of the methodology are assessed with simulation studies. The usefulness of the methods is illustrated with analyses of the effect modification of cholesterol and age on pravastatin in the multicenter placebo-controlled regression growth evaluation statin study. When a participant-level meta-analysis cannot be performed, aggregate-data interaction meta-analysis is a useful alternative for exploring individual-level sources of treatment effect heterogeneity. [ABSTRACT FROM PUBLISHER]
- Published
- 2013
- Full Text
- View/download PDF
47. A new measure of time-varying association for shared frailty models with bivariate current status data.
- Author
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Unkel, Steffen and Farrington, C. Paddy
- Subjects
TIME-varying systems ,MATHEMATICAL models ,ANALYSIS of variance ,STATISTICAL sampling ,SEROLOGY ,DISEASE susceptibility ,PARAMETER estimation - Abstract
In this paper, a new measure for assessing the temporal variation in the strength of association in bivariate current status data is proposed. This novel measure is relevant for shared frailty models. We show that this measure is particularly convenient, owing to its connection with the relative frailty variance and its interpretability in suggesting appropriate frailty models. We introduce a method of estimation and standard errors for this measure. We discuss its properties and compare it to an existing measure of association applicable to current status data. Small sample performance of the measure in realistic scenarios is investigated using simulations. The methods are illustrated with bivariate serological survey data on a pair of infections, where the time-varying association is likely to represent heterogeneities in activity levels and/or susceptibility to infection. [ABSTRACT FROM AUTHOR]
- Published
- 2012
- Full Text
- View/download PDF
48. Asymptotic Theory of Range-Based Multipower Variation.
- Author
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Christensen, Kim and Podolskij, Mark
- Subjects
ASYMPTOTIC theory of system theory ,ANALYSIS of variance ,MARKET volatility ,FINANCIAL economics ,MICROSTRUCTURE ,SIMULATION methods & models - Abstract
In this paper, we present a realized range-based multipower variation theory, which can be used to estimate return variation and draw jump-robust inference about the diffusive volatility component, when a high-frequency record of asset prices is available. The standard range-statistic—routinely used in financial economics to estimate the variance of securities prices—is shown to be biased when the price process contains jumps. We outline how the new theory can be applied to remove this bias by constructing a hybrid range-based estimator. Our asymptotic theory also reveals that when high-frequency data are sparsely sampled, as is often done in practice due to the presence of microstructure noise, the range-based multipower variations can produce significant efficiency gains over comparable subsampled return-based estimators. The analysis is supported by a simulation study, and we illustrate the practical use of our framework on some recent Trade and Quote (TAQ) equity data. [ABSTRACT FROM PUBLISHER]
- Published
- 2012
- Full Text
- View/download PDF
49. Distinguishing 6 Population Subgroups by Timing and Characteristics of the Menopausal Transition.
- Author
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Huang, Xiaobi, Harlow, Siobán D., and Elliott, Michael R.
- Subjects
AGE factors in disease ,AGING ,ALGORITHMS ,ANALYSIS of variance ,BIOMARKERS ,STATISTICAL correlation ,LONGITUDINAL method ,MATHEMATICAL models ,MENOPAUSE ,MENSTRUAL cycle ,RESEARCH funding ,STATISTICS ,TIME ,WOMEN ,SECONDARY analysis - Abstract
Changes in women’s menstrual bleeding patterns precede the onset of menopause. In this paper, the authors identify population subgroups based on menstrual characteristics of the menopausal transition experience. Using the TREMIN data set (1943–1979), the authors apply a Bayesian change-point model with 8 parameters for each woman that summarize change in menstrual bleeding patterns during the menopausal transition. The authors then use estimates from this model to classify menstrual patterns into subgroups using a K-medoids algorithm. They identify 6 subgroups of women whose transition experience can be distinguished by age at onset, variability of the menstrual cycle, and duration of the early transition. These results suggest that for most women, mean and variance change points are well aligned with proposed bleeding markers of the menopausal transition, but for some women they are not clearly associated. Increasing understanding of population differences in the transition experience may lead to new insights into ovarian aging. Because of age inclusion criteria, most longitudinal studies of the menopausal transition probably include only a subset of the 6 subgroups of women identified in this paper, suggesting a potential bias in the understanding of both the menopausal transition and the linkage between the transition and chronic disease. [ABSTRACT FROM PUBLISHER]
- Published
- 2012
- Full Text
- View/download PDF
50. Commentary: Hogben vs the Tyranny of Averages.
- Author
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Tabery, James
- Subjects
BIOLOGISTS ,GENETICISTS ,ANALYSIS of variance ,BIOMETRY ,STATISTICAL significance ,EXPERIMENTAL design ,GENOTYPE-environment interaction - Published
- 2011
- Full Text
- View/download PDF
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