• The omnibus or overall F test is the first of the two-step MANOVA process of analysis. It tests the null hypothesis that there is no difference in the means of the dependent variables for the different groups formed by categories of the independent variables. The multivariate formula for F is based not only on the sum of squares between and within groups, as in ANOVA, but also on the sum of crossproducts -- that is, it takes covariance into account as well as group means. Significance tests for multiple dependents (ex., Hotelling, Wilks, or Pillai tests) all follow the F distribution and so an F value and corresponding significance level are printed out for each of these tests in SPSS, in the section labeled "Analysis of Variance" (older versions) or "Multivariate Tests" (newer versions of SPSS). There are four leading tests of group differences: