From: <toby909_at_gmail.com>

Date: Sun, 16 Mar 2008 04:09:00 -0700

nx = nrow(x); nx

ny = nrow(y); ny

n = nx+ny; n

R-help_at_r-project.org mailing list

https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. Received on Sun 16 Mar 2008 - 11:29:49 GMT

Date: Sun, 16 Mar 2008 04:09:00 -0700

Hi

I spent hours looking over my formula. Somehow I cant find the reason why it gives me different answer.

x = as.matrix(read.table("http://www.niehs.nih.gov/research/atniehs/core/microarrays/docs/heinloth.txt",1)) x = t(x) #now rows are subjects, cols are genes x = x[order(rownames(x)),] #order by treatment group oxygen,ultra-violet, gamma radiation

y = x[26:45,1:10] x = x[2:25,1:10] p = ncol(x); p

nx = nrow(x); nx

ny = nrow(y); ny

n = nx+ny; n

# (t(x)-colMeans(x)) %*% t(t(x)-colMeans(x))

T2 = nx*ny/n * t(colMeans(x)-colMeans(y)) %*% solve( ( (nx-1)*cov(x)+(ny-1)*cov(y) )/( n-2 ) ) %*% (colMeans(x)-colMeans(y)); T2

library(ICSNP)

HotellingsT2(y,x)

http://en.wikipedia.org/wiki/Hotelling's_T-square_distribution

http://finzi.psych.upenn.edu/R/Rhelp02a/archive/60962.html

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https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. Received on Sun 16 Mar 2008 - 11:29:49 GMT

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