GLM = Equal variances [🇷 for BE/BA]

posted by Helmut Homepage – Vienna, Austria, 2010-04-26 16:45 (5085 d 18:55 ago) – Posting: # 5234
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Dear D. Labes and Yung-jin,

❝ Yesss Sir. But only if we assume equal variances within the groups.

❝ I do not have the power to know any way to get unequal variance assumption into Proc GLM.


❝ And at least the mighty FDA does not want it this way from us :no:.


FDA’s requirement is the justification for guideline-believers. I think it’s not by chance that FDA calls for procedures for unequal variances if they are available (specifically for parallel groups and replicate designs). Bad luck for 2×2 cross-overs (common variance part of the model).
IMHO good statistical practice would call for the Welsh-test; it’s also not by chance that var.equal = FALSE is the default in [image]’s t.test.

Dif-tor heh smusma 🖖🏼 Довге життя Україна! [image]
Helmut Schütz
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