[R] Cochran-Armitage

Chuck Cleland ccleland at optonline.net
Fri Dec 12 12:40:23 CET 2008


On 12/12/2008 3:29 AM, robert-mcfadden at o2.pl wrote:
> Hello,
> Which package allows to use Cochrana-Armitage trend test? I tried to search for but I found only package coin in which there is no explicit function.

  But there is this example in coin:

### Cochran-Armitage trend test for proportions
### Lung tumors in female mice exposed to 1,2-dichloroethane
### Encyclopedia of Biostatistics (Armitage & Colton, 1998),
### Chapter Trend Test for Counts and Proportions, page 4578, Table 2
lungtumor <- data.frame(dose = rep(c(0, 1, 2), c(40, 50, 48)),
                        tumor = c(rep(c(0, 1), c(38, 2)),
                                  rep(c(0, 1), c(43, 7)),
                                  rep(c(0, 1), c(33, 15))))
table(lungtumor$dose, lungtumor$tumor)

### Cochran-Armitage test (permutation equivalent to correlation
### between dose and tumor), cf. Table 2 for results
independence_test(tumor ~ dose, data = lungtumor, teststat = "quad")

  See the following:

http://finzi.psych.upenn.edu/R/library/coin/html/ContingencyTests.html

  There also is an implementation in the GeneticsBase package
(Bioconductor).

> Best,
> RobMac 
> 
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-- 
Chuck Cleland, Ph.D.
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