Tim Hesterberg wrote: >> values <- sapply(1:1000, function(i) sample(1:3, size=2, prob = c(.5, .25, >> .25))) >> table(values) >> > values > 1 2 3 > 834 574 592 > > The selection probabilities are not proportional to the specified > probabilities. > > In contrast, in S-PLUS: > >> values <- sapply(1:1000, function(i) sample(1:3, size=2, prob = c(.5, .25, >> .25))) >> table(values) >> > 1 2 3 > 1000 501 499 > > But is that the right thing? If you can use prob=c(.6, .2, .2) and get 1200 - 400 - 400, then I'm not going to play poker with you....
The interpretation in R is that you are dealing with "fat cards", i.e. card 1 is twice as thick as the other two, so there is 50% chance of getting the _first_ card as a 1 and additionally, (.25+.25)*2/3 to get the 2nd card as a 1 for a total of .8333. And since the two cards are different the expected number of occurrences of card 1 in 1000 samples is 833. What is the interpretation in S-PLUS? -- O__ ---- Peter Dalgaard Øster Farimagsgade 5, Entr.B c/ /'_ --- Dept. of Biostatistics PO Box 2099, 1014 Cph. K (*) \(*) -- University of Copenhagen Denmark Ph: (+45) 35327918 ~~~~~~~~~~ - ([EMAIL PROTECTED]) FAX: (+45) 35327907 ______________________________________________ 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.