The sample function can be used to sample discrete values with designated probabilities. I would just construct your list of 5 values based on the selected value (duplicating end values if needed, so a choice of x=0 would be the vector c(0,0,0, 0.125, 0.25) ), then sample from this vector with the probabilities that you specify.
On Mon, Jun 23, 2014 at 3:11 PM, Dan Abner <dan.abne...@gmail.com> wrote: > Hi all, > > I have the following situation and a good efficient way to perform > this operation in R has not come to me. Any suggestions/input are > welcome. > > I have a user-defined parameter (let's call it x) whose value is > selected from a set of possible values (j). Once the user selects one > of the values of j for x, then I need to map a probability > distribution to the values of j such that the middle probability of > .5385 (see probs below) is associated with the value of x and the tail > probabilities are assigned to the 2 values below x and 2 values above > x in j. Therefore, in the example below: > > > x<-.250 > j<-c(0.000,0.125,0.250,0.375,0.500,0.625,0.750,0.875,1.000) > probs<-c(0.02307692,0.20769231,0.53846154,0.20769231,0.02307692) > > probabilities would be assigned to the values of j as such: > > value probability > 0 0.023077 > 0.125 0.207692 > 0.25 0.538462 > 0.375 0.207692 > 0.5 0.023077 > > And then 1 value of j is selected based on the associated probability. > Any ideas on an efficient way to do this? > > An added dimension of complexity is when the value of x is selected > near the parameter boundary of j. If x = 0, then the easiest thing I > can think of is to assign probabilities as: > > value probability > 0 0.76923077 > 0.125 0.207692 > 0.25 0.023077 > > However, I am open to other possibilities. > > Any assistance is appreciated. > > Thanks, > > Dan > > ______________________________________________ > 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. -- Gregory (Greg) L. Snow Ph.D. 538...@gmail.com ______________________________________________ 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.