Brown-Forsythe F* Test for Two-way ANOVA

The Brown-Forsythe F* test is useful when the variances across the different groups are not equal. When the sample sizes are equal, we can use an extension of the Brown-Forsythe F* Test for One-way ANOVA.  Since the sample sizes are equal, F* = F and the individual df (dfA, dfB, etc.) are the same as for ANOVA. We only need to calculate the overall df as follows:

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where
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This df can be used for testing factor A, factor B or interaction effects. The test is

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3 Responses to Brown-Forsythe F* Test for Two-way ANOVA

  1. Colin says:

    Sir

    Could you give us an example about this topic? I don’t understand why the F test for A,B, and interaction factor has exactly the same 1st df and 2nd df.

    Colin

    • Charles says:

      Colin,
      Although I have described the Brown-Forsythe F* test for one-way Anova (and have included a function to carry out the test in the Real Statistics Resource Pack), I have not really given an adequate description for two-way Anova. Perhaps I should remove this webpage for now. I plan to provide a more complete description of the two-way test eventually, but have not yet given it a high enough priority. I am currently working on how to better handle missing data in regression (e.g. using FIML).
      Charles

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