[R] Chi-Square Test Disagreement

[Andrew Choens]

I was asked by my boss to do an analysis on a large data set, and I am
trying to convince him to let me use R rather than SPSS. I think Sweave
could make my life much much easier. To get me a little closer to this
goal, I ran my analysis through R and SPSS and compared the resulting
values. In all but one case, they were the same. Given the matrix

    [,1] [,2]
[1,]  110  358
[2,]   71  312
[3,]   29  139
[4,]   31   77
[5,]   13   32

This is the output from R:
> chisq.test(test29)

	Pearson's Chi-squared test

data:  test29
X-squared = 9.593, df = 4, p-value = 0.04787

But, the same data in SPSS generates a p value of .051. It's a small but
important difference. I played around and rescaled things, and tried
different values for B, but I never could get R to reach .051.

I'd like to know which program is correct - R or SPSS? I know, this is a
biased place to ask such a question. I also appreciate all input that
will help me use R more effectively. The difference could be the result
of my own ignorance.

thanks
--andy

-- 
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