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Levy, Kenneth J. – Educational and Psychological Measurement, 1976
A procedure is specified for testing the significance of predicted trends in k independent correlations. An example is also provided for illustrative purposes. (Author)
Descriptors: Correlation, Hypothesis Testing, Trend Analysis
Peer reviewed Peer reviewed
Levy, Kenneth J. – Educational and Psychological Measurement, 1977
The importance of the assumption of normality for testing that a bivariate normal correlation equals zero is examined. Both empirical and theoretical evidence suggest that such tests are robust with respect to violation of the normality assumption. (Author/JKS)
Descriptors: Analysis of Variance, Correlation, Hypothesis Testing
Peer reviewed Peer reviewed
Levy, Kenneth J. – Psychometrika, 1975
The Z-variance and Box-Scheffe tests for homogeneity of variance are both relatively simple to perform and readily utilized in complex, multi-factor designs. The Z-variance test is not robust against non-normality; the Box-Scheffe test is robust against non-normality but is not nearly as powerful as the Z-variance test. (Author/BJG)
Descriptors: Analysis of Variance, Comparative Analysis, Hypothesis Testing
Peer reviewed Peer reviewed
Levy, Kenneth J.; And Others – Educational and Psychological Measurement, 1978
It is suggested that Levy's procedure for testing predicted trends in independent correlations should not produce grossly incorrect inferences when one is dealing with the sorts of correlations which are ordinarily encountered in empirical research. (Author/JKS)
Descriptors: Correlation, Hypothesis Testing, Research Design, Trend Analysis
Peer reviewed Peer reviewed
Levy, Kenneth J. – Educational and Psychological Measurement, 1975
Proposes three different multiple range tests based upon the Newman-Keuls philosophy with respect to significance levels. The three tests utilize the Fmax statistic, Cochran's statistic and a normalizing log transformation of the sample variances respectively. (Author/RC)
Descriptors: Analysis of Variance, Comparative Analysis, Hypothesis Testing, Statistical Significance
Peer reviewed Peer reviewed
Levy, Kenneth J. – Psychometrika, 1974
Descriptors: Analysis of Variance, Hypothesis Testing, Models, Sampling
Peer reviewed Peer reviewed
Levy, Kenneth J. – Journal of Experimental Education, 1978
The purpose of this paper is to demonstrate how many more subjects are required to achieve equal power when testing certain hypotheses concerning proportions if the randomized response technique is employed for estimating a population proportion instead of the conventional technique. (Author)
Descriptors: Experimental Groups, Hypothesis Testing, Research Design, Response Style (Tests)
Peer reviewed Peer reviewed
Levy, Kenneth J. – Educational and Psychological Measurement, 1975
The Dunnett procedure for comparing several treatment means with a control is applied to the problem of comparing several treatment variances with the variance of a control. Appropriate critical values are specified and an example is provided. (Author)
Descriptors: Analysis of Variance, Comparative Analysis, Control Groups, Experimental Groups
Peer reviewed Peer reviewed
Levy, Kenneth J. – Journal of Experimental Education, 1978
Monte Carlo techniques were employed to compare the familiar F-test with Welch's V-test procedure for testing hypotheses concerning a priori contrasts among K treatments. The two procedures were compared under homogeneous and heterogeneous variance conditions. (Author)
Descriptors: Analysis of Variance, Comparative Analysis, Hypothesis Testing, Monte Carlo Methods
Peer reviewed Peer reviewed
Levy, Kenneth J. – Journal of Experimental Education, 1979
Hawkin's procedure for testing a sequence of observations for a shift in location could have applicability for assessing change within a single subject. Monte Carlo results suggest that Hawkins' procedure is robust with respect to moderate violations of its underlying assumptions of homogeneity of variance and normality. (Author/GDC)
Descriptors: Case Studies, Hypothesis Testing, Individual Development, Mathematical Models