[R] Two-way ANOVA gives different results using anova(lm()) than doing it by hand

[Marc Schwartz]

On Jul 8, 2009, at 12:11 PM, Greg Snow wrote:

> Well, since we don't have Data.txt it is kind of hard for us to  
> replicate what you have done.
>
> Here goes a guess as to what the problem may be.
>
> Have you told R anywhere that S1 and S2 are factors with 6 levels  
> rather than numeric vectors? Or are you just hoping that the  
> computer can read your mind to find out this information?
>
> (reading minds is one of the things that R and computers in general  
> are not very good at yet.  I have made a note to my future self to  
> use the TimeTravel package to send a copy of the ESP package back to  
> my past self, but I have not received it yet).


A definite Fortunes candidate.

Marc Schwartz