R help - Apr 2011 - Random Relabelling

I have 4000 observations that I need to randomly relabel 1000 times and then
calculate the mean of the 1000 values at each of the 4000 points.  Any ideas
for where to begin? 

Thanks
Kevin 

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Can you explain this a bit more. At the moment I don't see what you are
trying to achieve.   "calculate the mean of the 1000 values at each of the
4000 points" does not seem to make sense.

--- On Wed, 4/20/11, kmatthews <kevin-matthews at uiowa.edu> wrote:
> From: kmatthews <kevin-matthews at uiowa.edu>
> Subject: [R] Random Relabelling
> To: r-help at r-project.org
> Received: Wednesday, April 20, 2011, 10:04 AM
> I have 4000 observations that I need
> to randomly relabel 1000 times and then
> calculate the mean of the 1000 values at each of the 4000
> points.? Any ideas
> for where to begin? 
> 
> Thanks
> Kevin 
>

Hi:

How about

y <- rnorm(4000)
ymat <- rowMeans(replicate(1000, y[sample(4000)]))
hist(ymeans)

system.time({y <- rnorm(4000); yy <- rowMeans(replicate(1000,
y[sample(4000)]))})
   user  system elapsed
   0.19    0.03    0.22

HTH,
Dennis

On Wed, Apr 20, 2011 at 7:04 AM, kmatthews <kevin-matthews at uiowa.edu>
wrote:
> I have 4000 observations that I need to randomly relabel 1000 times and
then
> calculate the mean of the 1000 values at each of the 4000 points. ?Any
ideas
> for where to begin?
>
> Thanks
> Kevin
>
> --
> View this message in context:
http://r.789695.n4.nabble.com/Random-Relabelling-tp3463100p3463100.html
> Sent from the R help mailing list archive at Nabble.com.
>
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