[R] need help with chisq

David Winsemius dwinsemius at comcast.net
Sat May 9 23:18:37 CEST 2009

On May 9, 2009, at 4:53 PM, JC wrote:

> I am very new to R. I have some data from a CVS stored in vdata with 4
> columns labeled:
> X08, Y08, X09, Y09.
> I have created two new "columns" like so:
> Z08 <- (vdata$X08-vdata$Y08)
> Z09 <- (vdata$X09-vdata$Y09)
> I would like to use chisq.test for each "row"

Of what?

> and output the p-value
> for each in a stored variable. I don't know how to do it. Can you
> help?
> so far I have done it for one row (but I want it done automatically
> for all my data):
> chidata=rbind(c(vdata$Y08[1],Z08[1]),c(vdata$Y09[1],Z09[1]))

Maybe I am dense, but I cannot figure out what hypothesis is being  
> results <- chisq.test(chidata)
> results$p.value

Generally using apply(vdata, 1, ..... would give you a row by row  
> I tried removing the [1] and the c() but that didn't work...  Any
> ideas?

As Jim Holtman's tag line says: "What problem are you trying to solve?"

David Winsemius, MD
Heritage Laboratories
West Hartford, CT

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