[R] Difference in ANOVA results - R vs. JMP/Minitab

John Fox jfox at mcmaster.ca
Thu Nov 20 14:53:42 CET 2003

Dear Nirmal,

At 03:20 AM 11/20/2003 -0500, Nirmal Govind wrote:
>Thanks for your reply, Prof. Ripley.
>>And all of that is explained in the reference on the aov help page.
>>Please do stop speculating and start reading.
>Well, the reason for speculation was cos I couldn't find any details on 
>that help page... thanks for letting me know that the reference explains 
>>AoV has nothing to do with coefficients.  There is dummy.coef to get
>>uncoded coefficients, and there is options(contrasts=) to set the coding.
>Ok, I will try these...
>>Yes, you should read a lot more.  Chapter 6 of Venables & Ripley (2002) 
>>and chapter 5 of Chambers & Hastie (1991) would be a good start.
>Oh, I most definitely should! :-) .. I guess I was hoping that such 
>details would be included in the help page for the function or mentioned 
>in some R introduction or tutorial or so on the Documentation page.. looks 
>like that's not the case so I'll get a hold of the books above...

Actually, there's a decent basic explanation of these matters in Sec. 11 of 
the manual An Introduction to R, which comes with R. As Prof. Ripley points 
out, you'll find more detailed treatments in books.

John Fox
Department of Sociology
McMaster University
Hamilton, Ontario, Canada L8S 4M4
email: jfox at mcmaster.ca
phone: 905-525-9140x23604
web: www.socsci.mcmaster.ca/jfox

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