[R] calculating mean for samples

[stephen sefick]

assuming that A1 is the data provided in the first post... it would be
helpful if you used dput() to copy into an email, so that we could
just copy the code and data right into a R session and be off and
running.  I hope this helps.

#I used dput() on the object A1
A1 <- (structure(list(s1 = c(0L, 1L, 0L, 0L, 0L, 1L, 0L, 0L, 0L, 0L),
    s2 = c(0L, 0L, 0L, 0L, 1L, 0L, 0L, 0L, 0L, 0L), s3 = c(0L,
    1L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L), s4 = c(1L, 0L, 0L, 0L,
    1L, 0L, 0L, 0L, 0L, 1L)), .Names = c("s1", "s2", "s3", "s4"
), class = "data.frame", row.names = c(NA, -10L)))

f <- do.call(rbind , rep(A1[sample(nrow(A1), 5),], 5))
d <- apply(f, MARGIN=1, FUN=mean)
mean(d[names(d)==s1])
mean(d[names(d)==s2])
mean(d[names(d)==s3])
mean(d[names(d)==s4])

On Mon, Oct 20, 2008 at 2:44 PM, al ex <loyola9988 at yahoo.com> wrote:
> I dont have a problem with sampling and calculating mean:
>
> for(i in 1:5){
>  res=(A1[sample(nrow(A1), 5),])
>  Avg=colMeans(res)
>  STD=sd(res)
>  print(res)
>  print(Avg)
>  print(STD)
>  }
>
> my problem is how to save the mean for each "S" in each sample and calculate
> the grand mean
>
>
>
> --- On Mon, 10/20/08, stephen sefick <ssefick at gmail.com> wrote:
>
> From: stephen sefick <ssefick at gmail.com>
> Subject: Re: [R] calculating mean for samples
> To: "Alex99" <loyola9988 at yahoo.com>
> Date: Monday, October 20, 2008, 11:34 AM
>
> look at
> ?sample
> ?lapply
> ?mean
>
> On Mon, Oct 20, 2008 at 1:53 PM, Alex99 <loyola9988 at yahoo.com> wrote:
>>
>>
>  Hi everyone,
>>> does any one knows how can I calculate mean for different samples
>>> i.e. I have a data like this:
>>>
>>>  s1 s2 s3 s4
>>> 1   0  0  0  1
>>> 2   1  0  1  0
>>> 3   0  0  0  0
>>> 4   0  0  0  0
>>> 5   0  1  0  1
>>> 6   1  0  0  0
>>> 7   0  0  0  0
>>> 8   0  0  0  0
>>> 9   0  0  0  0
>>> 10  0  0  0  1
>>>
>>> I need to make 5 different sample with 5 different persons(rows) in
> each
>>> sample from it keeping s1,s3,s3,s4 but changing rows. and then
> calculate
>>> the mean for each "S" in each sample. and finally calculate
> the grand
>>> mean,which is the mean of means for each sample. i.e. if I sample 5
> time I
>>> get 5 different means for s1, s2, s3, s4. then I need to add all five
>>> means for and divide it by 5.(of course I have to do it
>  for
> s1,s2,s3,s4
>>> separately)
>> --
>> View this message in context:
> http://www.nabble.com/calculating-mean-for-samples-tp20075174p20075174.html
>> Sent from the R help mailing list archive at Nabble.com.
>>
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>>
>
>
>
> --
> Stephen Sefick
> Research Scientist
> Southeastern Natural Sciences Academy
>
> Let's not spend our time and resources thinking about things that are
> so little or so large that all they really do for us is puff us up and
> make us feel like gods.  We are mammals, and have not exhausted the
> annoying little problems of being mammals.
>
> 								-K.
>  Mullis
>
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-- 
Stephen Sefick
Research Scientist
Southeastern Natural Sciences Academy

Let's not spend our time and resources thinking about things that are
so little or so large that all they really do for us is puff us up and
make us feel like gods.  We are mammals, and have not exhausted the
annoying little problems of being mammals.

								-K. Mullis