Wald Wolfowitz Test, Mann-Whitney Test, Type I Error, Skewness, Kurtosis, Monte Carlo Study

2013 ◽  
Vol 5 (4) ◽  
pp. 188-195
Author(s):  
Otuken Senger
2020 ◽  
Vol 18 (1) ◽  
Author(s):  
Alyssa Counsell ◽  
Robert Philip Chalmers ◽  
Robert A. Cribbie

Comparing the means of independent groups is a concern when the assumptions of normality and variance homogeneity are violated. Robust means modeling (RMM) was proposed as an alternative to ANOVA-type procedures when the assumptions of normality and variance homogeneity are violated. The purpose of this study is to compare the Type I error and power rates of RMM to the trimmed Welch procedure. A Monte Carlo study was used to investigate RMM and the trimmed Welch procedure under several conditions of nonnormality and variance heterogeneity. The results suggest that the trimmed Welch provides a better balance of Type I error control and power than RMM.


1981 ◽  
Vol 48 (1) ◽  
pp. 19-22 ◽  
Author(s):  
James D. Church ◽  
Edward L. Wike

A Monte Carlo study was done to find the Type I error rates for three nonparametric procedures for making k − 1 many-one comparisons in a one-way design. The tests ( t) were the Silverstein and Steel many-one ranks tests and the two-sample Wilcoxon rank-sum test, k = 3, 5, 7, and 10 treatments were crossed with n = 7, 10, and 15 replicates with 1000 simulations per k, n combination. Analyses of four Type I error rates showed that: (1) The Wilcoxon test had the best comparisonwise error rates; (2) none of the tests functioned well as protected tests; and (3) the Silverstein test had the best experimentwise error rates and was the recommended procedure for many-one tests for a one-way layout.


2016 ◽  
Vol 77 (1) ◽  
pp. 104-118 ◽  
Author(s):  
Mengyang Cao ◽  
Louis Tay ◽  
Yaowu Liu

This study examined the performance of a proposed iterative Wald approach for detecting differential item functioning (DIF) between two groups when preknowledge of anchor items is absent. The iterative approach utilizes the Wald-2 approach to identify anchor items and then iteratively tests for DIF items with the Wald-1 approach. Monte Carlo simulation was conducted across several conditions including the number of response options, test length, sample size, percentage of DIF items, DIF effect size, and type of cumulative DIF. Results indicated that the iterative approach performed well for polytomous data in all conditions, with well-controlled Type I error rates and high power. For dichotomous data, the iterative approach also exhibited better control over Type I error rates than the Wald-2 approach without sacrificing the power in detecting DIF. However, inflated Type I error rates were found for the iterative approach in conditions with dichotomous data, noncompensatory DIF, large percentage of DIF items, and medium to large DIF effect sizes. Nevertheless, the Type I error rates were substantially less inflated in those conditions compared with the Wald-2 approach.


2020 ◽  
Author(s):  
Alyssa Counsell ◽  
R. Philip Chalmers ◽  
Rob Cribbie

Researchers are commonly interested in comparing the means of independent groups when distributions are nonnormal and variances are unequal. Robust means modeling (RMM) has been proposed as an alternative to ANOVA-type procedures when the assumptions of normality and variance homogeneity are violated. This paper extends work comparing the Type I error and power rates of RMM to those for the trimmed Welch procedure. A Monte Carlo study was used to investigate RMM and the trimmed Welch procedure under several conditions of nonnormality and variance heterogeneity. Our results suggest that the trimmed Welch provides a better balance of Type I error control and power than RMM.


1996 ◽  
Vol 123 (4) ◽  
pp. 333-339 ◽  
Author(s):  
William P. Dunlap ◽  
Tammy Greer ◽  
Gregory O. Beatty

1976 ◽  
Vol 1 (2) ◽  
pp. 113-125 ◽  
Author(s):  
Paul A. Games ◽  
John F. Howell

Three different methods for testing all pairs of yȳk, - yȳk’ were contrasted under varying sample size (n) and variance conditions. With unequal n’s of six and up, only the Behrens-Fisher statistic provided satisfactory control of both the familywise rate of Type I errors and Type I error rate on each contrast. Satisfactory control with unequal n’s of three and up is dubious even with this statistic.


1981 ◽  
Vol 49 (3) ◽  
pp. 931-934
Author(s):  
James D. Church ◽  
Edward L. Wike

A Monte Carlo study was done to find the Type I error rates for three nonparametric procedures for making k – 1 many-one comparisons in a two-way design. The tests were the Silverstein and Steel many-one tests and the two-sample step-down sign test. k = 3, 5, 7, and 10 treatments were crossed with n = 8, 11, and 15 blocks with 1000 simulations per k, n combination. The Silverstein test had the best experimentwise error rates and is recommended for many-one comparisons in a two-way design.


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