On Mon, May 28, 2012 at 12:14 PM, Özgür Asar oa...@metu.edu.tr wrote:
Dear Dila,
Try the following:
library(Rcmdr)
Or avoid the unncessary overhead of Rcmdr and use
library(car)
to provide levenTest instead.
asim - 1000
pv-NULL
It's also many orders of magnitude more efficient to preallocate pv
and then simply put things into it.
pv - vector(real, 1000)
for(i in 1:asim)
{
print(i)
set.seed(i)
Setting the seed each loop seems excessive but I suppose it's a matter
of taste.
g1 - rnorm(20,0,2)
g2 - rnorm(20,0,2)
g3 - rnorm(20,0,2)
x - c(g1,g2,g3)
Is there any reason not to do this as x - rnorm(60, 0, 2)
group-as.factor(c(rep(1,20),rep(2,20),rep(3,20)))
and this as as.factor(rep(1:3, each = 20))
pv-c(pv,leveneTest(x,group)$Pr(F)[1])
Once you preallocate pv change this to
pv[i] - leveneTest(x, group)$Pr(F)[1]
But it's even better not to use the dollar sign shortcut here
(defensive programming and all that -- particularly with nonstandard
names which I'm pretty sure won't give a big error here but will
elsewhere)
pv[i] - leveneTest(x, group)[[Pr(F)]][1]
And even better would be to do this all using the replicate
function, but I'll leave that as an exercise to the reader.
Michael
}
Best
Ozgur
-
Ozgur ASAR
Research Assistant
Middle East Technical University
Department of Statistics
06531, Ankara Turkey
Ph: 90-312-2105309
http://www.stat.metu.edu.tr/people/assistants/ozgur/
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