Welch versus Satterthwaith (PR#2111)

roxburg@kih.net roxburg@kih.net
Sat, 5 Oct 2002 22:27:49 +0200 (MET DST)

This is not a bug report but didn't see another way to ask a question.

For the approximate t-test assuming unequal variances, the R docs cite
Welch's method for the df of the approximating distribution.
I have several methods books, and they all uses Satterthwaite's method.
Why does R use Welch's method where can I learn about Welch's method?

David Allen

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