From: John Kane <jrkrideau_at_yahoo.ca>

Date: Wed, 20 Apr 2011 10:56:35 -0700 (PDT)

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. Received on Wed 20 Apr 2011 - 18:01:32 GMT

Date: Wed, 20 Apr 2011 10:56:35 -0700 (PDT)

There is probably a better way to do this but a for loop like this should work. You would just need to change the numbers to yours and then add on the locations

scores <- 1:5

mydata <- matrix(data=NA, nrow=5, ncol=10)

for(i in 1:10) {

mydata[,i] <- sample(scores, 5, replace=FALSE)
}

- On Wed, 4/20/11, Kevin Matthews <kevin-matthews_at_uiowa.edu> wrote:

From: Kevin Matthews <kevin-matthews_at_uiowa.edu>
Subject: Re: [R] Random Relabelling

To: "John Kane" <jrkrideau_at_yahoo.ca>

Cc: r-help_at_r-project.org

Received: Wednesday, April 20, 2011, 1:22 PM

I have a map of Iowa of with 4000 locations. At each location, I have a cancer mortality rate. I need to test my null hypothesis; that the spatial distribution of the mortality rates is random. For this test, I need to establish a spatial reference distribution.

My reference distribution will be created by some random relabelling algorithm. The 4000 locations would remain fixed, but the observed mortality rates would be randomly redistributed. Then, I want 1000 permutations of the same algorithm. For each of those 1000 times, I would record the redistributed mortality rate at each location. Then, I would calculate the mean of the 1000 points. The result would be a spatial reference distribution with a mean value of the random permutations at each of the 4000 locations.

Thanks for the response,Kevin

On Wed, Apr 20, 2011 at 11:08 AM, John Kane <jrkrideau_at_yahoo.ca> wrote:

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.

*> From: kmatthews <kevin-matthews_at_uiowa.edu>
*

*> Subject: [R] Random Relabelling
*

> 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
*

*>
*

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