From: Grathwohl, Dominik, LAUSANNE, NRC-BAS <dominik.grathwohl_at_rdls.nestle.com>

Date: Wed 12 Jul 2006 - 00:52:15 EST

, nrow=4, ncol=4, byrow=TRUE)

cm2 <- matrix(c(0, 1, 0, 1/2, 0, 0, 1, 1/2), nrow = 2, ncol=4, byrow=TRUE,

language R

R-help@stat.math.ethz.ch mailing list

https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html Received on Wed Jul 12 01:08:54 2006

Date: Wed 12 Jul 2006 - 00:52:15 EST

cov1 <- matrix(c(3/4,-1/2,-1/2,-1/2,1,0,-1/2,0,1), nrow = 3, ncol=3, byrow=TRUE,

dimnames = list(c("A", "B", "C"), c("C.1", "C.2", "C.3")))

# cov1 = variance covariance matrix of the beta coefficients of a

# 2x2 factorial design (see Piantadosi 2005, p. 509)

cm1 <- matrix(c(0, 1, 0, 0, 0, 1), nrow = 2, ncol=3, byrow=TRUE,

dimnames = list(c("A", "B"), c("C.1", "C.2", "C.3")))

# cm1 = contrast matrix for main effects

v1 <- csimint(estpar=c(100, 6, 5), df=4*n-3, covm=cov1*sigma^2/n, cmatrix=cm1, conf.level=0.95) summary(v1)

The adjusted p-values are almost the Bonferroni p-values.
If I understood right: You need not to adjust for multiple testing
on main effects in a 2x2 factorial design
assuming the absence of interaction.

I do not think that there is a bug,

I want to understand, why multcomp does adjust for multiple tests
having all information about the design of the trial (variance covariance matrix)?
Or do I have to introduce somehow more information?

c(1,-1,-1, 1, -1, 2, 1,-2, -1, 1, 2,-2, 1,-2,-2, 4)

, nrow=4, ncol=4, byrow=TRUE)

cm2 <- matrix(c(0, 1, 0, 1/2, 0, 0, 1, 1/2), nrow = 2, ncol=4, byrow=TRUE,

dimnames = list(c("A", "B"), c("C.1", "C.2", "C.3", "C.4"))) v2 <- csimint(estpar=c(100, 6, 5, 2), df=4*n-4, covm=cov2*sigma^2/n, cmatrix=cm2, conf.level=0.95) summary(v2)

arch i386 os mingw32 system i386, mingw32 status major 2 minor 2.1 year 2005 month 12 day 20 svn rev 36812

language R

R-help@stat.math.ethz.ch mailing list

https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html Received on Wed Jul 12 01:08:54 2006

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