Re: [R] Lack of independence in anova()

From: Douglas Bates <dmbates_at_gmail.com>
Date: Thu 07 Jul 2005 - 03:28:42 EST

On 7/6/05, Phillip Good <pigood@verizon.net> wrote:
> Do you or Lumley have a citation for this conclusion? Most people go
> forward with the ANOV on the basis that the various tests are independent.
>
> Phillip Good
> P.S. Tests based on the method of synchronized permutations are
> independent.

Perhaps we could review the sequence of events here. This exchange began with your sending me a message claiming that there is a bug in lm or anova in R because the results of your simulation were what you expected. I responded saying that it is unlikely that a serious bug in such a fundamental part of R would remain undetected for such a long time and then went further and took apart your simulation and showed how it could be done much more effectively and also showed, with help from Thomas Lumley and Peter Dalgaard, that your original assumption is incorrect.

You have now made another blanket statement the "Most people go forward with the ANOV on the basis that the various tests are independent" and indicated that Thomas or I should provide a citation to validate our claim. Perhaps instead of claiming that it is necessary for us to produce evidence in support of our claim that they are not independent because they are based on the same denominator mean square, you could produce a citation to back up your claim. To date none of your claims of the independence of the tests or the supposed bugs in R have been substantiated. If indeed "most people" do as you claim then "most people" are suffering from a misconception, a not-uncommon situation in statistics.



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https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html Received on Thu Jul 07 03:33:41 2005

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