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/
> --
> View this message in context:
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>
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