simtest for Dunnett's test

Before you do any of that, you should realize the fact that simtest does
_not_ do Dunnett's test:  It can use `Dunnett' _contrasts_ to do comparisons
with a control, but the actual procedure is different.  You are unlikely to
get the same result as other packages that perform standard Dunnett's test
(or Tukey's, for that matter).

Andy

From: Laurent Houdusse

Hi!

I use simtest fonction of multcomp package to compile a
Dunnett's test.
I have 10 treatments and one control group, so i create a matrix with:

m<-matrix(0,10,11)
m[1,1]<--1
m[1,2]<-1
m[2,1]<--1
m[2,3]<-1
m[3,1]<--1
m[3,4]<-1
m[4,1]<--1
m[4,5]<-1
m[5,1]<--1
m[5,6]<-1
m[6,1]<--1
m[6,7]<-1
m[7,1]<--1
m[7,8]<-1
m[8,1]<--1
m[8,9]<-1
m[9,1]<--1
m[9,10]<-1
m[10,1]<--1
m[10,11]<-1
rownames(m)<-c("vehicle+vehicle vs. morphne
60mg/kg+vehicle","vehicle+vehicle vs. Naloxone
30mg/kg+vehicle","vehicle+vehicle vs. Naloxone 30mg/kg+Morphine
60mg/kg","vehicle+vehicle vs. RWJ-69528-000-B
0.1mg/kg+vehicle","vehicle+vehicle vs. RWJ-69528-000-B
1mg/kg+vehicle","vehicle+vehicle vs. RWJ-69528-000-B 0.1mg/kg+morphine
60mg/kg","vehicle+vehicle vs. RWJ-69528-000-B 1mg/kg+morphine
60mg/kg","vehicle+vehicle vs. vehicle+acetaminophen
600mg/kg","vehicle+vehicle vs. RWJ-69528-000-B 0.1mg/kg+acetaminophen
600mg/kg","vehicle+vehicle vs. RWJ-69528-000-B 1mg/kg+acetaminophen
600mg/kg")
y<-c(21.5,14.7,16.7,18.8,17.3,15.527,17.551,17.199,15.895,14.3
88,30,30,30,21
.2,14.6,30.83,30.622,30.465,24.563,31.416,30,30,30,30,19.6,17.
61,30.346,20.8
,17.045,18.129,17.9,15.4,30,15.9,22.9,31.909,25.633,24.6,20.35
5,18.807,30,18
.9,16.4,18.2,22.3,21.3,28.571,17.357,16.983,30.40,26.3,24.4,25
,24.1,14.4,10.
256,13.266,29.6,15.344,18.69,30,30,25.7,30,28.5,30,30.32,30,19
.879,30.716,25
.2,30,30,30,30,30,14.063,28.811,30.396,30.609,30,14.1,30,30,30
,26.322,30.386
,28.583,15.77,29.341,30,17.1,30,30,30,30,20.451,30,23.967,30.5
07,30,30,30,27
.7,30,28.5,22.568,32.379,30.374,28.263)
h<-factor(c(rep(1:11, each = 10)))
result<-summary(simtest(y ~ h,cmatrix=cbind(0,m)))
rownames(result$estimate)
result


I want to compare my results with the results obtained with SigmaStat
Software.
In my results, i retrieve a correct q' value with the simtest t value
How can i say if P<0.05 like the SigmStat results?
Can i use p raw value, p bonf value, p adj value or other to compare
directly? Or can i use the Dunnett's tables?

Thanks for your help!




Laurent Houdusse
Analyste Programmeur