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)

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)

A series of independent, normally distributed events may be broken into intervals on an a priori basis. Then, within interval variance may be compared to among interval variance. These might be considered short-term and long-term variances. This concept and a test for comparing variances are presented. (Author/JKS)

Two potentially useful tests for homogeneity of variance--the jackknife test and the Box test--are described and compared. Recommendations for the use of these techniques and computational examples of each are provided. (Author/JKS)

This paper briefly describes unplanned and planned methods of evaluating differences between means and explains orthogonal versus nonorthogonal contrasts to help the researcher understand a framework of planned comparisons. A small heuristic data set is generated to illustrate the superiority of planned comparisons over omnibus analysis of…

A particular strategy for investigating effects resulting from a multivariate analysis of variance (MANOVA) is proposed. The strategy involves multiple two-group multivariate analyses. The two groups result from considering multivariate pairwise group contrasts or multivariate complex group contrasts. Assuming a given two-group analysis yields…

Although analysis of variance is the most popular statistical tool to researchers in the behavioral sciences, the casual user has recognized only recently that there is no single correct way to perform such an analysis. This paper is concerned with hypotheses tested in the two-way, fixed model under a variety of conditions: (1) with and without…

The conduct of multiple post hoc comparison procedures following an analysis of variance is discussed. Various procedures are contrasted in terms of appropriateness, power, and other features. Octhogonal and nonorthogonal comparisons are discussed. (JKS)

Several ways of using traditional analysis of variance to test the homogeneity of variance in factorial designs with equal or unequal cell sizes are compared using theoretical and Monte Carlo results. (Author/JKS)

A problem in analysis of variance is that after rejection of the overall hypothesis, no contrasts of interest are found to be significant. A procedure for determining the contrast of significance is outlined, and the relationship between the "most significant" contrast and the overall test is shown. (Author/JKS)

A simple rationale for Scheffe's Method and Gabriel's Simultaneous Test Procedure is presented. Examples of both methods are provided. (Author)

The use of multiple comparisons in analysis of variance (ANOVA) is discussed. It is argued that experimentwise Type I error rate inflation can be serious and that its influences are often unnoticed in ANOVA applications. Both classical balanced omnibus and orthogonal planned contrast tests inflate experimentwise error to an identifiable maximum.…

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)