[R-sig-ME] how to get satterthwaite/Kenward-Roger degrees of freedom for heterogeneous-variance one-way ANOVA from an object of nlme::gls

[Qiu, Weiliang /US]

Dear Dr. Turner,

Thanks for the information!

Best regards,

Weiliang

-----Original Message-----
From: Rolf Turner <rolfturner using posteo.net> 
Sent: Thursday, October 17, 2024 9:53 PM
To: Qiu, Weiliang /US via R-sig-mixed-models <r-sig-mixed-models using r-project.org>
Cc: Qiu, Weiliang /US <Weiliang.Qiu using sanofi.com>
Subject: Re: [R-sig-ME] how to get satterthwaite/Kenward-Roger degrees of freedom for heterogeneous-variance one-way ANOVA from an object of nlme::gls


On Wed, 16 Oct 2024 14:42:24 +0000
"Qiu, Weiliang /US via R-sig-mixed-models"
<r-sig-mixed-models using r-project.org> wrote:

> Greetings. I am using nlme::gls() to perform heterogeneous-variance 
> one-way ANOVA and would like to get type III anova table.

<SNIP>

One should always think very carefully about what hypotheses are actually being tested in a "type III analysis".  Such an analysis may well be "meaningful" but the hypotheses being tested may not be of any real interest. They involve taking averages of cell means over the levels of factors and these averages may not describe anything pertinent.

cheers,

Rolf Turner

--
Honorary Research Fellow
Department of Statistics
University of Auckland
Stats. Dep't. (secretaries) phone:
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