[R] Help Help with sampling

[Alex99]

Thanks for the reply Jorge,

that works BUT the reason I didn't use it, is because I need to calculate
the mean and Standard deviation for S1,S2,S3 and S4 in each sample. which
means I'll have 5 means for S1, and 5 means for S2 and 5 means for S3 and 5
means for S4 (and at the end I have to get the average of the means for each
'S').
I used the following:

for(i in 1:5) {temp<-sample(A3,3, replace=F)
+ Trans=t(temp)
+ Avg=mean(Trans)
+ show(temp)
+ show(Trans)
+ show(Avg)}

the reason I used Transpose is to get the R to give me the mean for S's. but
what I get is just one mean for each sample. not the mean for each S.
any suggestion how to do it?

thanks again for all your help 

Jorge Ivan Velez wrote:
> 
> Dear Alex,
> Is this what you want?
> 
> # Data set
> my=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(my)=paste('s',1:4,sep="")
> 
> # Samples
> res=list()
> for(i in 1:5) res[[i]]<- my[,sample(colnames(my),5)]
> res
> 
> HTH,
> 
> Jorge
> 
> 
> On Wed, Oct 15, 2008 at 10:07 AM, Alex99 <loyola9988 at yahoo.com> wrote:
> 
>>
>> Hi everyone,
>>
>> I have a dataset(named "Mydata") which includes 4 different variables
>> named;
>> s1,s2,s3,s4 .Each variable(symptom) has 14 patients.
>> I need to use random sampling to make, 5 different samples from my data
>> with
>> 5 patients in each sample. i.e. using all 4 variables I need to make 5
>> different samples by changing patients(with 5 patients in each sample).
>>
>>
>>   X8 X9 X10 X102 X110 X177 X283 X284 X286 X292 X297 X306 X308 X314
>> s1  0  1   0    0    0    1    0    0    0    0    0    0    0    0
>> s2  0  0   0    0    1    0    0    0    0    0    0    0    1    0
>> s3  0  1   0    0    0    0    0    0    0    0    0    0    1    0
>> s4  1  0   0    0    1    0    0    0    0    1    0    0    0    0
>>
>>
>> I used this code:
>>
>> temp=list(NULL)
>> for(i in 1:5) {temp[i]<-sample(Mydata,5, replace=F)} show(temp)
>>
>> but I get the following error:
>> "number of items to replace is not a multiple of replacement length"
>>
>> any idea why I get this eeror message and how can I fix it?
>> Thanks a lot.
>>
>> --
>> View this message in context:
>> http://www.nabble.com/Help-Help-with-sampling-tp19994275p19994275.html
>> Sent from the R help mailing list archive at Nabble.com.
>>
>> ______________________________________________
>> R-help at 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.
>>
> 
> 	[[alternative HTML version deleted]]
> 
> ______________________________________________
> R-help at 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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