Dear Alex,
Just a _minor_ change in the function "powers":
# powers
# n is the number of samples
# DATA is the ORIGINAL data set
powers=function(n,m2,n2,s2,DATA){
outp=Sample(DATA,n) # DATA was 'name' before, which doesn't make
sense
mymeans=outp$Gmean
mysds=outp$Gsd
res=t(rbind(mymeans,mysds,n=n))
apply(res,1,Power,m2=m2,n2=n2,s2=s2)
}
HTH,
Jorge
On Fri, Oct 17, 2008 at 4:01 PM, Jorge Ivan Velez
<[EMAIL PROTECTED]>wrote:
>
> Dear Alex,
> Try this:
>
>
>
> # Data
> name=read.table(textConnection("
> X8 X9 X10 X102 X110 X177 X283 X284 X286 X292 X297 X306 X308 X314
> 0 1 0 0 0 1 0 0 0 0 0 0 0 0
> 0 0 0 0 1 0 0 0 0 0 0 0 1 0
> 0 1 0 0 0 0 0 0 0 0 0 0 1 0
> 1 0 0 0 1 0 0 0 0 1 0 0 0
> 0"),header=TRUE)
> closeAllConnections()
> rownames(name)=paste('s',1:4,sep="")
>
> # Sample
> # Function to estimate both the big mean and big standard deviation
> # name is the data set
> # n is the number of samples
> Sample=function(name, n){
> res=replicate(n,name[,sample(colnames(name),n)],simplify=FALSE)
> Means=do.call(rbind,lapply(res,function(x) rowMeans(x)))
> rownames(Means)=paste('sample',1:n,sep="")
> Gmean=colMeans(Means)
> STDs=do.call(rbind,lapply(res,function(x) apply(x,1,sd)))
> rownames(STDs)=rownames(Means)
> Gsd=sd(STDs)
> list(Gmean=Gmean,Gsd=Gsd)
> }
>
> # Power
> # mypars is a vector of length three which components
> # are n1, s1 and n1
> # m2, s2 and n2 may change
> # alfa is "fixed"
> Power=function(mypars,m2,s2,n2,alfa=0.05){
> m1=mypars[1]
> s1=mypars[2]
> n1=mypars[3]
> up=abs(m1-m2)
> down=sqrt(((s1^2)/(n1))+((s2^2)/(n2)))
> z=(-1)*(qnorm(1-(alfa/2)))
> fi=z+(up/down)
> pow=pnorm(fi)
> return(pow)
> }
>
> # powers
> # n is the number of samples
> # DATA is the ORIGINAL data set
> powers=function(n,m2,n2,s2,DATA){
> outp=Sample(name,n)
> mymeans=outp$Gmean
> mysds=outp$Gsd
> res=t(rbind(mymeans,mysds,n=n))
> apply(res,1,Power,m2=m2,n2=n2,s2=s2)
> }
>
>
> # ten samples and values for m2, n2 and s2
> powers(n=10,m2=0.12,n2=10,s2=0.15)
>
>
> HTH,
>
> Jorge
>
>
> On Fri, Oct 17, 2008 at 11:50 AM, Alex99 <[EMAIL PROTECTED]> wrote:
>
>>
>> Hi everyone,
>> I have dataset which I make a sample of it couple of times and each time I
>> get the mean and standard deviation of each row for each sample. I have a
>> function for that, which takes the name of the file and number of times to
>> sample and then returns the mean and standard deviation for each row in
>> each
>> sample.
>>
>> Sample=function(name, n){
>> res=replicate(n,name[,sample(colnames(name),n)],simplify=FALSE)
>>
>> Means=do.call(rbind,lapply(res,function(x) rowMeans(x)))
>> rownames(Means)=paste('sample',1:n,sep="")
>> Gmean=colMeans(Means)
>>
>> STDs=do.call(rbind,lapply(res,function(x) rowSds(x)))
>> rownames(STDs)=paste('sample',1:5,sep="")
>> Gsd=sd(STDs)
>>
>> return(Gmean,Gsd)}
>>
>> I then need to use the mean and standard deviation from each row to
>> calculate the Power for 2 sample means. here is the function I use to do
>> it:
>>
>> Power=function(alfa,m1,m2,s1,s2,n1,n2){
>> up=abs(m1-m2)
>> down=sqrt(((s1^2)/(n1))+((s2^2)/(n2)))
>> z=(-1)*(qnorm(1-(alfa/2)))
>> fi=z+(up/down)
>> pow=pnorm(fi)
>> return(pow)}
>>
>> then I need to call the Power function:
>>
>> Power(.05,57,mi,33,si,200,n)
>>
>> the alfa,m1,s1 and n1 values are constant but the m2,s2 and n2 values are
>> changing.
>> n2 is the n used in sample function(which I could input manually)
>> m2 should be the grand mean for each row
>> s2 is the grand standard deviation for each row
>>
>> example:this is a sample output for "sample" function:
>> $Gmean
>> s1 s2 s3 s4
>> 0.08 0.20 0.12 0.20
>>
>> $Gsd
>> s1 s2 s3 s4
>> 0.2449490 0.2156741 0.2449490 0.2156741
>> my problem is how can I put the corresponding means and standard
>> devotions
>> together in the power function?I used a for loop, but the problem is
>> getting the s1...s4 from Gmean and Gsd
>>
>> Thanks for your help
>>
>>
>> --
>> View this message in context:
>> http://www.nabble.com/function-help-tp20035949p20035949.html
>> Sent from the R help mailing list archive at Nabble.com.
>>
>> ______________________________________________
>> R-help@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.
>>
>
>
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