On 2010-07-14 6:47, martanair wrote:
the value of the F-test is uncorrect. If I calculate the Levene's Test for Homogeneity of Variance with SPSS I get F = 5.128 Pr (> F) = 0.033 Why?
Why do you assume that SPSS provides the "correct" value?
what is the exact formula which R calculate Levene's test for two groups?
John Fox has explained the formula used in pkg:car. You can also have a look at Wikipedia (see "Brown-Forsythe test"). Finally, this won't be necessary with John's new version of car, but pkg:lawstat has a levene.test() function that lets you select the statistic to center your groups on. SPSS uses the mean, car uses the median. -Peter Ehlers ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
