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The article discusses the pattern in vegetation, in which the peaks in the graph of mean square against block size are interpreted. To analyze the peaks in the graph, a logarithmic transformation to both the variance and the spacing is applied, and fitted a polynomial regression of log-variance on log-spacing. The apparent fit by linear regressions results from failure to allow for the occurence of overall trends in representation of species, the rising curve to be expected for random distribution, and the application of logarithmic transformation to the variance data.

The article discusses the effects of accounting variations on decision making and the paper "An Experimental Design for Study of Effects of Accounting Variations in Decision Making" by R.E. Jensen. The statistical methodology and design used by Jensen in his research of the effects of alternative accounting reporting techniques in the selection of portfolios and their security evaluation is examined as is the data collection. The limitation of whether or not there was adequate control over the research environment and the probability level of the statistical tests is not known in Jensen's paper because he does not mention these issues.

The purpose of the present paper is to examine the adequacy of variance as a measure of risk. Despite the abundance of literature on risk and portfolio diversification, virtually all of which uses variance as the measure of risk, there has been little progress on this problem beyond the original contributions. Tobin has pointed out that variance is the appropriate measure of risk if either the probability distribution of returns can be fully described by two parameters (e.g., normal) or the investor utility functions can be approximated by quadratics. Markowitz has suggested the possibility of using the semi-variance as a measure of risk, but for the most part his analysis of risk and portfolio diversification closely parallels that of Tobin. The subsequent literature has in general used variance as a measure of risk without further consideration. Moreover, those studies which have examined the measurement of risk explicitly either have provided only minor modifications to the Tobin-Markowitz analysis or have proposed alternative measures of risk which have been generally ignored. Thus, whether for reasons of convenience, theory or tradition, variance continues to be almost universally used as the measure of risk in portfolio models. The present paper takes a different approach to the problem of using variance as a measure of risk and reaches the conclusion that variance is ambiguous and yields conflicting results when calculated from information generally available to decision makers. If variance is in fact the best measure of risk (and thus appropriate for computing the locus of efficient portfolios and calculating the discount for uncertainty in capital asset prices) the question remains: which variance? In the case of a stock portfolio, the variance in the rate of return for an individual stock may be calculated from price information recorded over a shorter or longer period of time; moreover, observations from the same period of time when aggregated u... [ABSTRACT FROM AUTHOR]

The author discusses the pattern analysis of variance of sample estimates of plant cover changes as the distance between samples increases. The author mentions the disagreement between his work and the data from the similar studies conducted by Greig-Smith at Bangor. The author argues that variance between samples could often be satisfactorily represented by a linear regression connecting log variance with log spacing; and that in any case such a linear regression would account for by far the major part of the differences in variance observed.

Recently Simkowitz and Jones have noted the potential importance of the tools of multivariate analysis and simultaneous equation estimators of econometrics as tools for finance methodology. They note that empirical research in finance dealing with such variables as the value of financial securities has used, almost exclusively, cross sectional analysis "... where all firm effects other than those described by the independent variables are assumed away." More extensive estimation efforts require either the use of other multivariate techniques, such as cannonical correlation (for correlating sets of variables) or more explicit modeling of the structure of the relationships between, say, different firms' securities' prices before the simultaneous equations estimators can be successfully employed. The purpose of this paper is to propose an approach that is intermediate between these extremes but which will allow us to gauge the importance of unexplained joint effects as between different securities' prices. Additionally, it provides a means of extending the methods proposed by Fried for estimating single asset return equations as an input to the Markowitz model. [ABSTRACT FROM AUTHOR]

This paper reports an empirical test of the usefulness of a prediction method for multivariate budgets suggested by Theil. The method, based on information theory concepts, is described in the first three sections, and results of the test are presented in the remaining sections. These results show that the suggested prediction method outperforms both the actual forecasts made by the firms who provided the data and two naive forecasts. [ABSTRACT FROM AUTHOR]

The article presents a response to the paper "Observations on Jensen's Experimental Design for Study of Effects of Accounting Variations in Decision Making" by Thomas R. Dyckman and discusses the scale of observation in an analysis of variance (ANOV) model. Dyckman questions Jensen's research in proposing violations in the underlying assumptions of the ANOV model and whether or not these violations would appreciably affect the conclusions of his experiment. An interval scale was used during some of Jensen's data selection for discussion which Dyckman feels is incorrect in its additivity assumption.

In this paper, we present evidence that local trends do exist in the Standard and Poor's Index. We begin by assuming that the logarithm of the price at time t[sub 1], say log P(t[sub 1]), has an expected value which is a linear function of time. That is, E log P(t[sub 1]) = at[sub 1] + b where a and b are arbitrary but fixed constants. Then we use the techniques of the analysis of variance to test whether any constants in the expression above satisfy the data. The tests show that these data are not explained by such an expected value. We conclude that the mean is different (certainly more complicated than at[sub 1] + b) over different intervals of time. The changes in expected value over these intervals are referred to as local trends. Finally, by repetition of the tests for different interval sizes, we find that the tests are significant for interval sizes up to approximately one year but not longer. Thus the evidence suggests that the local trends, when they occur, do not last longer than this period of time. [ABSTRACT FROM AUTHOR]

The article presents a study about the multivariate methods in plant ecology giving a comparison of information-analysis and association-analysis. This paper focuses on selected agglomerative-polythetic methods used in hierarchical classification for their efficiency in ecological investigations. Classifications of similarity methods in the past experiments are presented for further understanding. The author explores the appropriate stopping-rules for agglomerative-polythetic and information-analysis where he suggests a non-probabilistic rule based on heterogeneity of groupings in large-scale vegetation survey.

The conventional analysis of variance applied to designs in which each subject is measured repeatedly requires stringent assumptions regarding the variance-covariance (i.e., correlations among repeated measures) structure of the data. Violation of these assumptions results in too many rejections of the null hypothesis for the stated significance level. This paper considers several alternatives when heterogeneity of covariance exists, including nonparametric tests, randomization and matching procedures, Box and Greenhouse-Geisser corrections, and multivariate analysis. The presentation is from an applied rather than theoretical standpoint. Multivariate techniques that make no covariance assumptions and provide exact probability statements represent the most versatile solution. [ABSTRACT FROM AUTHOR]

The paper presented by Fertig et al. has approached the problem of repeated measures over time in a most appropriate form showing most definitively, as they state in the multi-group case, that the multivariate methods are more flexible and robust than those of the univariate analysis of variance. In the multi-group repeated measures design they have shown that the underlying assumptions of the analysis of variance approach are rarely, if ever, met; and the sphericity criterion test, which rejected even the less restrictive model assumptions as given in Huynh and Feldt, demonstrated this quite adequately, I think. The appropriate overall tests of significance were then given in both univariate and multivariate form in order to test the various hypotheses connected with the repeated measure-s design over time. Although the discussant may appear to differ in his multiple comparison approach, it is merely an extension of the overall tests as given by Fertig et al. and is only a different view of the sources of significance than those of discriminant vector analysis as utilized by Fertig et al. [ABSTRACT FROM AUTHOR]

This paper presents a follow-up records' study of 773 former marriage counseling clients of 21 marriage counselors. The clients' primary treatment form was compared with six categories of counseling outcome. A chi-square statistical treatment demonstrated that the six forms of counseling resulted in different outcomes significant beyond the .001 level. A rank ordering of the six forms for effectiveness suggested conjoint interviews and conjoint groups to be the most effective forms. Different forms may be helpful to those who divorce as opposed to those remaining married, and some findings are quite different from current supposition. [ABSTRACT FROM AUTHOR]

The paper considers the estimation of the parameters of the regression model where the dependent variable is normal but truncated to the left of zero. Tobin [8] first considered the problem and proposed an iterative solution of the maximum likelihood equations. The paper proves the strong consistency and the asymptotic normality of the maximum likelihood estimator, proves the inconsistency of Tobin's initial estimator, proposes a computationally simple estimator that is consistent and asymptotically normal, and proves the asymptotic efficiency of the second-round estimator in the method of Newton. An extension to the case where the observations are not available at the truncation point is briefly indicated in the Conclusions. [ABSTRACT FROM AUTHOR]

The article focuses on age and a group test battery as predictors of types of crime. Age and a group test battery were used to predict types of crimes committed by offenders, classified according to offense as classified into three groups: crimes against persons, crimes against property, and paper-and-pencil crimes. The data were analyzed by a stepwise discriminate function regression analysis. The cases were classified correctly into the three groups by the tests, when compared to actual crimes committed better than would be expected by chance.

The article presents a study about a multivariate approaches to the ecology of algae on terrestrial rock surfaces in North Wales. This paper focused on the quantitative and qualitative data collected from two restricted areas which looked into the ecology of terrestrial algae. A review of the epilithic algae is included providing the phytosociological information on the algae. Subjective classifications were done on algae communities. The present study involved modern techniques of investigation using multivariate analysis of tropical freshwater algae.

In either simple or multivariate regression models, measured coefficients represent a kind of average of co-variant relationships implicit in the data. For time-series data, if co-variant relationships follow no particular pattern over the sample period, use of this average in forecasting is rational. However, if relationships among independent and dependent variables is undergoing change over time, then measured regression coefficients are likely to be poor tools for prediction. This paper is an exploratory study of this general problem area. It develops implications as to the predictive impact of the problem and offers preliminary suggestions as to a method of developing predictions under such circumstances. [ABSTRACT FROM AUTHOR]

This paper examines the theoretical and empirical bases of the election law in Great Britain. The law itself appears to have been suggested for the first time by the Retired Honorable James Parker Smith in evidence before the Royal Commission on Systems of Elections of 1909. Smith emphasized the disparity between the strength of the representation of a party in the House of Commons and its share of the votes in the whole country. Since Edgeworth and P. A. McMahon considered the relation of seats to votes, the rise of a third majority voting in Britain, but in the 1935, 1945 and 1950 general elections the two-party system effectively returned and, despite some hopes to the contrary, seems likely to remain in force in the foreseeable future. The proportion calculated for each constituency is of the votes cast for the party winning a majority in the House of Commons to the combined votes of the major parties in that constituency. Voters cannot be regarded as scattered at random over the various constituencies. Since the observed distribution of proportion is very close to the normal form and the normal form itself is closely represented by the law of the cubic proportion, it follows that the observed distribution of proportion may be represented by the cube-law provided that it has the correct variance. At any election, therefore, in which the distribution of proportion is normal, variation in the standard deviation of proportion from 0.136788 will produce the effect that a higher or lower power than the third will be required to raise the votes ratio to the seats ratio.

The adaptations of plants to environment can take many morphological and physiological forms. The rate at which new plant material is accumulated is an integrated measure of plant response to environment and is a useful character when comparing either genetic differences between populations or effects of different environmental conditions on populations. Several approaches have been made to the study of quantitative plant growth. With frequent harvesting, regression analysis provides a powerful tool in describing the relationship of total weight with time. In this paper we have adopted procedures outlined by Draper and Smith (1966) and applied regression analysis to two sets of data from our programme on Atriplex. These demonstrate ways in which appropriate polynomial regression equations can be objectively applied to the total weight-time relationship. Implications of fitting an inappropriate regression equation and the problems of extrapolation are also discussed. [ABSTRACT FROM AUTHOR]

Tables of critical points for the noncentral F are presented with noncentrality equal to ½ of numerator degrees of freedom for denominator degrees of freedom of 1-30, 40, 60, 120, 200, 400, and 1,000, and numerator degrees of freedom of 1-30, 40, 60, 120, and 200, and type one errors of 0.05, 0.10, 0,25, and 0.50. These critical points can be used to test the second weak MSE criterion discussed in the companion paper. An approximation is suggested for noncentral F(θ), and accuracy checks are given. An appendix provides a Fortran function for the approximation. The approximation is intended for using the first weak MSE test discussed in the companion paper. [ABSTRACT FROM AUTHOR]

Facial expressions are an available source of information in most interpersonal situations and they are important in the communication of emotional meaning. The study presented in this paper investigates facial expressions as particular cases of stance and attempts to test the basic assumption that people can learn to duplicate facial expressions. Whether people can learn to duplicate facial expressions may at first seem purely academic and also perhaps obviously true. Yet neither of these conclusions seems to be the case. Facial expression duplication could be an important addition to the framing of clinicians to use these nonverbal cues better in their work with people Training in the laboratory with their own expressions and with those of others could transfer to the clinical situation, for example, in the following way suggested by Frieda Fromm-Reichmann. In an attempt to get an experimental baseline of research on this presupposition, pilot work was undertaken to demonstrate that a person can assume a particular stance, in this case his own and others' facial expressions. Since an experimental design could not be found which suited the collection of data for this study, the author devised one specifically for the purpose. Thus, in addition to testing some hypotheses, the author was also creating and trying out a new design for experimental work on facial expressions.

The article discusses the use of a graphomotor projective technique to discriminate between failure and success reactions in a level of aspiration situation. In this study a level of aspiration procedure with false reporting of achievement scores was used to create conditions of failure and success, and a modification of a graphomotor projective test. The time score data for performance of the Kohs Block Designs, the level of aspiration trends, and the goal discrepancy trends were analyzed by analysis of variance. The analysis showed that there were no differences in the trends of the time scores. A level of aspiration procedure was employed to create success and failure conditions and the ability of a graphomotor projective technique to discriminate between these conditions was analyzed.

The article discusses a method of weighting attitude scale items from subject responses. The most widely used technique for studying attitudes is the "rating scale" method. The scale usually consists of a group of statements which have been assigned differential weights. The subject indicates which statements he endorses and his final score may be the mean, median, or sum of weights for the endorsed statements. The purpose of this paper is to present a method of weighting attitude scale items from the responses of subjects. An attitude scale of 45 statements was constructed and administered to 586 students who were all freshmen at the University of South Carolina. Each statement was weighted according to a system based on the number of times it was endorsed by members of this group.

The article comments on psychologist Mark Baldwin's work. Baldwin has discussed problems in handling the time dimension in the statistical analysis of data regarding a single individual. In discussing temporal trends he has distinguished between the two types of dependence of the data with respect to time series. Certainly this is a very desirable distinction which Baldwin has suggested and it appears that much is to be gained from separating the variance in terms of factors of this type. The methods of analysis of variance and covariance lend themselves especially well to such separation as is proposed.

This paper describes an iterative procedure for obtaining maximum likelihood estimates of the parameters of a generalized regression model when direct maximization with respect to all parameters is difficult. A proof of convergence and some interesting applications are provided. [ABSTRACT FROM AUTHOR]

The preliminary test estimator lot predictor) is studied in the context of linear normal regression models. The estimator (or predictor) obtained after the preliminary test is known to be inadmissible with respect to squared error loss under certain assumptions. Nevertheless, it is still widely used in practical application of regression analysis, particularly in econometrics. The object of the present paper is to tabulate the optimal significance points in the preliminary test for practical use. The optimality is based on the minimax regret principle. It is shown that if, as is usual, we take the significance point equal to the 5 per cent point or 10 per cent point, the risk is extremely large for some parameter value. The optimal significance point of the preliminary t test decreases slightly as the degrees of freedom increase, but it is nearly constant; i.e., it lies between 1.370 to 1.380 if d.f. is greater than 6. [ABSTRACT FROM AUTHOR]

The purpose of this study was to compare two methods of analyzing EKG data, period (R-R intervals) and frequency (heart rate). Simulated data as well as EKGs recorded from newborn infants were utilized to show the effects of transforming cardiac periods into frequencies. The results showed that this transformation introduces errors, which are reflected in the mean, variance, and the degree of skewness of the basic data. It is argued that the widely used convention of transforming period data into heart rate should not be used without valid justification. [ABSTRACT FROM AUTHOR]

The article reports on the discussion of the mathematical concepts and behavior. The experimental study of behavior considers the development of mathematical concepts as a cognitive domain and must be studied with motivational controlled variables. The teaching of mathematical concepts must involve several levels of research. At one level, an examination of how concepts are acquired by children in certain situations. Through observation and examinations, the development of laws that describe the transfer of an already learned response to the acquisition of a subsequent response is possible.

The article cites a study regarding differences in some personal characteristics of rigid and flexible individuals. In this study, 500 subjects ranging in age from 20 to 70 years were divided into ten five-year age intervals. The ten most flexible and ten most rigid individuals in each group were examined with respect to certain of their personal characteristics. Results of an analysis of variance gave significant differences in favor of the flexible group on the measures of: years of education, income level, occupational level, self-ratings of happiness, success and social responsibility.

The article responds to an article by R. Mead in the March 1971 issue of the "Journal of Ecology," which proposes a unified mathematical approach to the analysis of ecological observations. It mentions that Mead has mistakenly interpreted his article as an advocacy of the use of multiple regression analysis for fitting high degree polynomial expressions to such observations. It states that the purpose of a first mathematical representation is to provide an intelligible description of observational data.

The article points out a number of misconceptions about the usage of regression models in ecology. The first misconception to be removed is that multiple regression is valid only when the independent variables are uncorrelated. Another misconception is that the estimated regression coefficient for a specific variable in multiple regression represents the dependence of the dependent variable on this independent variable only for the particular values of the other independent variables occurring in the data sample.

The article presents an introduction to the study on error analysis for quantitative chemistry. The author aims to introduce some of the problems of error in scientific measurement such as errors encountered in doing laboratory procedure due to the limitations on the precision of the equipment used. Examples are derived from quantitative analysis and concentrate on error in gravimetric and volumetric work. The method is not limited on the field of chemistry but is also applicable to the other field of sciences where quantitative data are taken in the laboratory and the precisions of the instruments are either known or can be approximated. Different publication related to the study is also included in the list of references.

The cumulative frequencies are obtained from the phi size-distribution moments (duly corrected for random sectioning) based on either weight or number frequency thin-section size data by the use of Gram-Charlier approximation. From the cumulative frequency distribution the various size-distribution statistics can be easily obtained and these statistics are useful for purposes of comparison, correlation, and interpretation of size data. [ABSTRACT FROM AUTHOR]

The article discusses a multiple linear regression approach to the evaluation of instructional strategies in science. They have described a treatment by levels experimental design and the methods required for forming and solving research problems associated with it. Multiple linear regression is a conceptually simple and powerful approach to the formation and resolution of a wide variety of research problems including the evaluation of instructional methods. The principles expressed in the study can be applied to other research problems as an effective alternative to the two-way analysis of variance.

The article presents a study in the U.S. investigating the effects of Free versus Guided Experimentation as approaches in science teaching. The population tested was 68 teachers in three separate science workshops. The four-celled experimental design involved the following variables: a pretest, reading matter and materials to be manipulated. From the Analysis of Variance it can be seen that the pretest is a highly significant motivator for finding the answers to specific questions asked. The result suggests that the best of both possible worlds seem attainable by Free Experimentation followed by flowchart discussion.

The article presents an analysis of the results of the "Is of Identity" test used to measure the differences in identification between science and non-science majors. 360 individuals enrolled in the College of Education at the Arizona State University were involved in the study. The influence of intelligence was controlled by a statistical technique called the analysis of variance with co-variance adjustment. The hypothesis tested states that an important underlying reason for an individual's orientation to science is his appropriate use of language or language patterns of a structure similar to that of the non-verbal world.

This paper develops an iterative procedure for estimating "specific" and "income" consumer unit scales in Engel curve analysis. The proposed procedure is essentially a modification of the Prais and Houthakker method and is illustrated by means of a numerical example based on the Indian National Sample Survey data. [ABSTRACT FROM AUTHOR]

This paper deals with two single-equation estimators in a set of simultaneous linear stochastic equations-namely, ordinary least squares (OLS) and two-stage least squares (2SLS). Under the assumption' that all predetermined variables in the model are exogenous, necessary and sufficient conditions are obtained for the existence of even moments of the above estimators. It is shown that for the general case with an arbitrary number of included endogenous variables, even moments of the 2SLS estimator are finite if and only if the order is less than K2 - G1 + 1. Furthermore, even moments of the OLS estimator exist if and only if the order is less than N - K1 - G1 + 1 where N is the sample size, G1 + 1 is the number of included endogenous variables, K1 and K2 respectively are the number of included and excluded exogenous variables in the equation to be estimated. [ABSTRACT FROM AUTHOR]

The standard F test for linear restrictions in regression is relevant as a criterion but fails to capture the notion of tradeoff between bias and variance. Average squared distance criteria yield operational tests that are more appropriate, depending upon objectives. In the present paper two alternative criteria are developed. The first allows testing of the hypothesis that the average squared distance of a restricted estimator from the parameter point in k space is less than the average squared distance of the unrestricted, ordinary least squares estimator from the same parameter point The second sets up a test of betterness of the restricted estimator over the unrestricted estimator of E(Y∣X), where betterness is again defined in average squared distance. [ABSTRACT FROM AUTHOR]

Occipital EEG was monitored during long-term exposure to visual stimulus arrays of five levels of complexity. Integrated EEG output was recorded for nine separate frequency bands. The stimuli were two, four, eight, 16 or 32 randomly located white squares on a black background. Mid-alpha activity (8·5-10·5 Hz) decreased linearly with log2n, where n = number of squares in the array (P < 0.01). Beta activity (12·5-16·5 Hz) showed a quadratic trend (P < 0-02). Theta activity (5·5-7·5 Hz) increased linearly with ascending complexity (P < 0·05). There were no significant trends for low alpha (7·5-8·5 Hz) or high alpha (10·5-12·5 Hz). Brightness-control slides showed no parallel effects. [ABSTRACT FROM AUTHOR]

This paper presents the results of an analysis of differences in "source traits," selected values, and aspirations of boys residing on farms, in rural nonfarm and village areas, and in small urban areas of a Michigan county. The data include questionnaire measurements of Cattell's 16 "source traits," several work-related value orientations, as well as educational and occupational aspirations of all of the 17-year-old boys in the county in school in the spring of 1957. Inasmuch as those from the various residence categories differ somewhat in socioeconomic status, the relationship of residence to personality orientations is tested with socioeconomic status (modified Sewell scores) controlled at two levels, middle class and lower class. Analysis of variance is used to test effects of residence and residence-by-status interaction on mean scores of 26 personality orientation variables. Residence is associated with 14 of these and interaction is associated with 6. Of the 26, a total of 18 are associated with either residence or interaction or both. This finding gives strong support to the hypothesis of rural-urban differences in personality orientations. Tentative post hoc interpretations are suggested. These concern possible personality consequences of rural-urban social structural differences in work and interpersonal behavior. [ABSTRACT FROM AUTHOR]

This article presents a response to criticisms on a research which evaluated the acceptability of three normative methods in insurance decision making. The authors of this article agree and so stated in their research that knowledge of the best act could affect a subject's rating of each normative method according to the specific criteria. It is interesting to note, however, that a subject's over-all view of the acceptability of a method did not automatically determine his ratings on specific criteria. For instance, subjects' ratings of the utility method varied to a considerable extent on the different criteria. As a result, the utility method compared more favorably with the other two methods according to some criteria than on an over-all basis.

The article investigates the efficiency of the Bender-Gestalt Test with the Background Interference Procedure with respect to organic mentally retarded patients, cultural-familial mentally retarded patients and emotionally disturbed mentally retarded patients. The results of the analysis of variance and of the Duncan multiple range test revealed that there was a significant difference between the organic group and two non-organic groups but that there was no significant difference between the cultural-familial and emotionally disturbed groups.

The article investigates the relationship between bank stock values and specific non-operating components of earnings in financial statements. The authors found a correlation between the operating earnings per dollar of assets and discounted bank stock values. Although the evidence to support the link between stock values and non-operating earnings components is weak, the authors claim that there is enough evidence to warrant further research. The authors reject that the value of stocks are not related to realized and unrealized security gains by properly utilizing regression analysis.

Levis sample clearly gives evidence of the TSF method's viability. But his research method tends to ignore the accounting issues involved. Accumulation of evidence is not sufficient from this standpoint. Rather, accumulation and synthesis in light of use should be the objective. I have focused mainly on the decision of which prediction model to employ, given the problem of allocating marginal predictions. Viewed in this light and experimental biases aside, we see three fundamental limitations. First, the comparisons are made in a highly specific manner with no attention given to either alternative error measures or statistical analyses. Second, no structural analyses were presented that would give any indication whatever of the types of situations in which certain variants of the method are likely to be useful. Third, the entire experiment relates to predicting individual items given marginal totals; and we must recognize that other basic methods of predicting individual items could be employed. Thus, by focusing on predictive ability per se rather than on the decision issue of selecting a prediction model, Lev has failed to develop the accounting (that is informational) issues in his experiment. [ABSTRACT FROM AUTHOR]

The article examines several alternative methods of computing variances. The author discusses the relationship between information and decisions and the alternation of a control policy. The author states that there are alternative methods of computing variances so that management is faced with the problem of choosing an optimum method and explains that the operational use of this criterion requires explicit knowledge of the firm's goals and decision processes. The article also discusses the significance of the firms. [ABSTRACT FROM AUTHOR]

The article investigates portfolio adjustment in the presence of non-negativity constraints. After establishing an investor's preference function and expectations for return, the author develops a model where constraints on short-selling prevail for at least some securities in the portfolio. The impact on the portfolio of changes in the mean return and variance of constituent securities is discussed, as well as the effect of changes in covariances between securities. Impacts are described in terms of a security's proportion of the overall portfolio.

Comments on a research which evaluated the acceptability of the three normative methods in insurance decision making. Preference for the best act under each normative method; Analysis of variance of the data presented; Implications of the weaknesses of the research design for insurance decision making.

The purpose of undertaking repeat examinations in oral epidemiology has been discussed. Since many of the published methods of demonstrating repeatability do not allow the influence of error to be quantified, the value of estimating reliability was investigated. This is based of the assumption that the coefficient of reliability is the ratio or true to total variance, where total variance is the sum of true and error variance. It was suggested that the reliability coefficient together with error variance should be used to express repeatability in oral epidemiology since reliability is closely related to the efficiency of the study and allows the relative importance of error to be assessed. Five methods for determining the reliability of dental caries data have been investigated and compared; all but one required the reexamination of subjects. The fifth method, although not requiring a reexamination, was considered unsuitable for use in caries studies. The two methods recommended for use in prevalence surveys were simple to use and provided data from which the reliability of incremental scores might be calculated. [ABSTRACT FROM AUTHOR]

This article reviews a computer-based method to predict transit time parameters (mean and variance) from historical data for use in logistics planning analysis. Efficient use of the data depends on relating it to a grid system of the United States. Performance of the technique on a sample of shipments by four methods of transportation is compared to a system based solely on highway distance. The techniques perform equally well for average transit time (speed). The grid system method demonstrates superior predicting power for reliability (transit time variance). Use of the system in daily operations is also anticipated. [ABSTRACT FROM AUTHOR]

22 male Ss, aged 44½-5½, were observed at home in 2 conditions: play and television viewing (TV), with order of conditions counterbalanced. 12 behaviors were rated for 55 min in each condition. The main effects of a 3-way analysis of variance (TV vs. play; high vs. low viewers; TV 1 vs. TV 2) indicated that as compared with play, TV was associated with significantly (p < .05) less talking, walking, object aggression, leaving the room, and maternal control and more attention shifts, sitting, and self-stimulation. Low weekly viewers self-stimulated more than highs during television and shifted attention less during play. Implications of increased television viewing for early socialization were discussed. [ABSTRACT FROM AUTHOR]