[R] comparing strength of association instead of strength of evidence?

[Weiwei Shi]

Hi,
I asked this question before, which was hidden in a bunch of
questions. I repharse it here and hope I can get some help this time:

I have 2 contingency tables which have the same group variable Y. I
want to compare the strength of association between X1/Y and X2/Y. I
am not sure if comparing p-values IS the way  even though the
probability of seeing such "weird" observation under H0 defines
p-value and it might relate to the strength of association somehow.
But I read the following statement from Alan Agresti's "An
Introduction to Categorical Data Analysis" :
"Chi-squared tests simply indicate the degree of EVIDENCE for an
association....It is sensible to decompose chi-squared into
components, study residuals, and estimate parameters such as odds
ratios that describe the STRENGTH OF ASSOCIATION".

Can I do this "decomposition" in R for the following example including
2 contingency tables?

> tab1<-array(c(11266, 125, 2151526, 31734), dim=c(2,2))
> tab1
      [,1]    [,2]
[1,] 11266 2151526
[2,]   125   31734

> tab2<-array(c(43571, 52, 2119221, 31807), dim=c(2,2))
> tab2
      [,1]    [,2]
[1,] 43571 2119221
[2,]    52   31807


BTW, is there some good forum on the theory of statistics? r-help is a
good one but I don't want to bother people by asking some questions
weakly associated with R here.

Thanks,

-- 
Weiwei Shi, Ph.D

"Did you always know?"
"No, I did not. But I believed..."
---Matrix III