[R] chi-squared test

[Peter Dalgaard BSA]

"juli g. pausas" <juli at ceam.es> writes:

> I don't quite understand the difference between the two methods for
> performing a chi-squared test on contingency tables:  summary(table())
> and   chisq.test()
> They may different results. E.g.:
> 
> aa <- gl(2, 10)
> bb <- as.factor(c(1,2,2,2,1,2,1,2,2,2,1,2,2,2,1,1,1,2,1,1))
> aa <- c(aa, aa)
> bb <- c(bb, bb)
> table(aa, bb)
> summary(table(aa, bb))
> chisq.test(aa, bb)
> 
> Could somebody give me some clues?
> Thanks in advance

The summary method is not doing Yates' correction.

-- 
   O__  ---- Peter Dalgaard             Blegdamsvej 3  
  c/ /'_ --- Dept. of Biostatistics     2200 Cph. N   
 (*) \(*) -- University of Copenhagen   Denmark      Ph: (+45) 35327918
~~~~~~~~~~ - (p.dalgaard at biostat.ku.dk)             FAX: (+45) 35327907
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