--- On Mon, 4/25/11, kmatthews <kevin-matth...@uiowa.edu> wrote:
> From: kmatthews <kevin-matth...@uiowa.edu> > Subject: Re: [R] Random Relabelling > To: r-help@r-project.org > Received: Monday, April 25, 2011, 10:53 AM > Thanks to everyone... this helps a > lot. Just a quick question about > etiquette in this forum (as it my first time > questioning)... are notes of > gratitude usually given in these forums? Certainly and thanks > > On Wed, Apr 20, 2011 at 1:26 PM, jthetzel [via R] < > ml-node+3463799-950416470-231...@n4.nabble.com> > wrote: > > > Kevin, > > > > The following follows John's suggestion, but without > the loop. It's quick > > for me. > > > > Jeremy > > > > > > Jeremy T. Hetzel > > Boston University > > > > > > > > ## Generate sample data > > n <- 4000 > > rep <- 1000 > > rate <- rnorm(n, mean = 15, sd = 2) / 100000 # > Mortality rates around > > 15/100k > > > > ## Create an empty matrix with appropriate dimensions > > permutations <- matrix(ncol = n, nrow = rep) > > > > ## Use apply() to resample > > permutations <- apply(permutations, 1, function(x) > > { > > sample(rate, size = n, replace = F) > > }) > > > > ## Look at the matrix > > dim(permutations) > > head(permutations) > > > > ## Find the column means > > means <- apply(permutations, 1, mean) > > means > > > > > > > > > > > > On Wednesday, April 20, 2011 1:56:35 PM UTC-4, John > Kane wrote: > > > > > > > > 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 <[hidden > email]<http://user/SendEmail.jtp?type=node&node=3463799&i=0&by-user=t>> > > wrote: > > > > > > From: Kevin Matthews <[hidden > > > email]<http://user/SendEmail.jtp?type=node&node=3463799&i=1&by-user=t>> > > > > > Subject: Re: [R] Random Relabelling > > > To: "John Kane" <[hidden > > > email]<http://user/SendEmail.jtp?type=node&node=3463799&i=2&by-user=t>> > > > > > Cc: [hidden > > > email]<http://user/SendEmail.jtp?type=node&node=3463799&i=3&by-user=t> > > > 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 > <[hidden > email]<http://user/SendEmail.jtp?type=node&node=3463799&i=4&by-user=t>> > > 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. > > > > > > --- On Wed, 4/20/11, kmatthews <[hidden > email]<http://user/SendEmail.jtp?type=node&node=3463799&i=5&by-user=t>> > > wrote: > > > > > > > From: kmatthews <[hidden > > > > email]<http://user/SendEmail.jtp?type=node&node=3463799&i=6&by-user=t>> > > > > > > > > > Subject: [R] Random Relabelling > > > > > > > To: [hidden > > > > email]<http://user/SendEmail.jtp?type=node&node=3463799&i=7&by-user=t> > > > > > > > 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 > > > > > > > > > > > > > > > > [[alternative HTML version deleted]] > > > > > > ______________________________________________ > > > [hidden > > > email]<http://user/SendEmail.jtp?type=node&node=3463799&i=8&by-user=t>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. > > > > > > > > ______________________________________________ > > [hidden > > email]<http://user/SendEmail.jtp?type=node&node=3463799&i=9&by-user=t>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. > > Jeremy T. Hetzel > > Boston University > > > > > > ------------------------------ > > If you reply to this email, your message will be > added to the discussion > > below: > > http://r.789695.n4.nabble.com/Random-Relabelling-tp3463100p3463799.html > > To unsubscribe from Random Relabelling, click > here<http://r.789695.n4.nabble.com/template/NamlServlet.jtp?macro=unsubscribe_by_code&node=3463100&code=a2V2aW4tbWF0dGhld3NAdWlvd2EuZWR1fDM0NjMxMDB8MTg3NTE4Mzk1OA==>. > > > > > > > -- > View this message in context: > http://r.789695.n4.nabble.com/Random-Relabelling-tp3463100p3473298.html > Sent from the R help mailing list archive at Nabble.com. > [[alternative HTML version deleted]] > > ______________________________________________ > 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. > ______________________________________________ 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.