Using apply for two datasets

Perhaps you can convert your matrices to data frames as in:

mapply(t.test,as.data.frame(myData1),as.data.frame(myData2))
to test by column and

mapply(t.test,as.data.frame(t(myData1)),as.data.frame(t(myData2)))


to test by row?


----- Original Message ----
From: Gang Chen <gangchen6 at gmail.com>
To: Henrique Dallazuanna <wwwhsd at gmail.com>
Cc: r-help at stat.math.ethz.ch
Sent: Tuesday, January 6, 2009 10:10:44 AM
Subject: Re: [R] Using apply for two datasets

Thanks a lot for the quick help!

mapply() seems promising. However, mapply(t.test, myData1, myData2)
would not work, so how can I specify the margin in mapply() which
function t.test() will be applied over? For example, I specify the 2nd
dimension (column) in apply(myData1, 2, t.test) to run one-sample
t-test. Is there a way I can achieve the same with mapply()?

Thanks again,
Gang

I think that you can use mapply for this.

On Tue, Jan 6, 2009 at 3:24 PM, Gang Chen <gangchen6 at gmail.com> wrote:

I can run one-sample t-test on an array, for example a matrix myData1,
with the following

apply(myData1, 2, t.test)

Is there a similar fashion using apply() or something else to run
2-sample t-test with datasets from two groups, myData1 and myData2,
without looping?

TIA,
Gang

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