From: Mary Black <mhbridge_at_usc.edu>

Date: Tue, 18 Mar 2008 15:28:47 -0700

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 Tue 18 Mar 2008 - 22:37:36 GMT

Date: Tue, 18 Mar 2008 15:28:47 -0700

After scouring the online R resources and help pages, I still need clarification on the function rmultinomial(). I would like to create a vector, say of 100 elements, where every element in the vector can take on the value of 0, 1 or 2, and where each of those values have a specific probability. ie. the probability a given element in the vector = 0 is 0.06, 1 = 0.38, 2 = 0.56 (probabilities sum to 1). Can I use rmultinomial() function to do this?

The following code does not seem to produce the result I need, but this sort of code is all I could find the R "help" pages:

> rmultinomial(100,c(0.06,0.38,0.56))

[1] 3 29 68

> rmultinomial(100,c(0.06,0.38,0.56),long=TRUE)

[1] 3 3 2 2 3 2 3 3 2 3 2 3 3 3 2 2 3 3 2 3 1 2 3 3 3 3 3 3 2 3 3 2 3 3 3 2 3 2 2 3 2 3 2 3 3 3 2 1 3 3 1
[52] 2 3 2 2 3 3 2 2 2 1 3 3 2 3 3 3 3 2 3 3 3 3 2 3 2 3 3 2 3 3 2 3 3 2 3 2 3 3 2 3 3 3 2 3 2 2 2 2 2

Also, I don't really understand the difference between the default long=FALSE and long=TRUE. The R "help" simply states that you use "long TRUE to choose one generator, FALSE to choose another one"; however I could not find any documentation that described what the difference between those generators is. Any clarification would be greatly appreciated!

Thanks,

Mary

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 Tue 18 Mar 2008 - 22:37:36 GMT

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