Search

Based on a chi square transform of the multivariate normal data set, we proposed a technique for testing multinormality which is the sum of interpoint squared distances between an ordered set of the transformed observations and the set of the population pth quantiles of the chi squared distribution. The critical values of the test were evaluated for different sample sizes and random vector dimensions through extensive simulations. The empirical type-I-error rates and powers of the proposed test were compared with those of some other well known tests for MVN with the proposed test showing excellent results at large sample sizes. [ABSTRACT FROM AUTHOR]

In this paper, a probability plots class of tests for multivariate normality is introduced. Based on independent standardized principal components of a d-variate normal data set, we obtained the sum of squared differences between corresponding observations of an ordered set of each principal component observations and the set of the population pth quantiles of the standard normal distribution. We proposed the sum of these d-sums of squared differences as an appropriate statistic for testing multivariate normality. We evaluated empirical critical values of the statistic and compared its power with those of some highly regarded techniques with a wonderful result. [ABSTRACT FROM AUTHOR]

This research investigated the prevalence of waterborne infections (WBIs) and the risks associated with household drinking water choices, knowledge, and practices. A cross-sectional multi-stage sampling research design was employed. A well-structured questionnaire was used to sample 403 individuals representing 115 household; and stool samples collected and subjected to standard parasitic and bacterial diagnostic methods. From the 403 samples, 344 (85.4%) were positive for at least one waterborne pathogen of nine isolates: E. coli (38.0%), Giardia lamblia (35.2%), E. histolytica (33.0%), Salmonella typhi (19.9%), Proteus spp. (13.2%), Shigella dysentery (9.4%), Klebsiella spp. (7.4%), Enterobacter spp. (5.5%), and Cryptosporidium spp. (5.2%). Prevalence of WBIs was >75% in all age groups, but decreased with age. Prevalence of WBIs was >80% in all communities. Risk was not biased by gender. Odds of infection from public well (OR = 2.487; CI 95 : 1.296-4.774) and borehole/vendor (OR = 2.175; CI 95 : 1.231-3.843) users was over two times greater than non-users. Risk of WBDs was significantly reduced by 60% in sachet water drinkers (OR = 0.392; CI 95 : 0.217-0.709; p < 0.05). Surprisingly, river/stream water users had a significant reduced risk of WBDs than non-users (OR = 0.335; CI 95 : 0.150-0.749; p < 0.05). Poor hygiene was the most important determinant of WBIs; poor sanitary practice increased odds of WBIs by 400% (OR = 4.945; CI 95 : 2.358-10.371; p < 0.05). This study shows that most household water choices are vulnerable to contamination at many points in their journey from source to mouth; and advocates adequate provision of safe water, "point of use" household water treatment, and good storage methods to effectively curb WBIs., Competing Interests: Conflicts of interest: The authors declare that there was no conflict of interest., (© 2020 the Author(s), licensee AIMS Press.)