Thanks so much, Chuck and Mark. Here's my script to simulate 10,000 rolls of 100 fair dice to demonstrate their conformity to a normal curve: > x<-replicate(10000, sum(sample(1:6,100,replace=T))) > sdx<-sd(x) > sdx [1] 17.13966 > meanx<-mean(x) > meanx [1] 350.0451 > hist(x, freq=FALSE) > curve(dnorm(x, mean=meanx, sd=sdx), add=TRUE) >
Thanks, again, for your quick and accurate help. -Kevin -----Original Message----- From: Charles C. Berry [mailto:[EMAIL PROTECTED] Sent: Monday, October 08, 2007 1:56 PM To: Zembower, Kevin Cc: [EMAIL PROTECTED] Subject: Re: [R] Dice simulation: Getting rep to re-evaluate sample()? See ?replicate which I think is what you are after. Chuck On Mon, 8 Oct 2007, Zembower, Kevin wrote: > I'm trying to get R to simulate the sum of the values on 10 fair dice > (yes, it's related to a homework problem, but is not the problem > itself). I tried to do this: >> rep(sum(sample(1:6,100,replace=T)), times=10) > [1] 341 341 341 341 341 341 341 341 341 341 > > and noticed that sum(sample()) seems to be only evaluated once. How can > I overcome this, so that I get a vector of values that correspond to > independent throws of 10 dice each time? > > Thanks for your advice and suggestions. > > -Kevin > > Kevin Zembower > Internet Services Group manager > Center for Communication Programs > Bloomberg School of Public Health > Johns Hopkins University > 111 Market Place, Suite 310 > Baltimore, Maryland 21202 > 410-659-6139 > > ______________________________________________ > 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. > Charles C. Berry (858) 534-2098 Dept of Family/Preventive Medicine E mailto:[EMAIL PROTECTED] UC San Diego http://famprevmed.ucsd.edu/faculty/cberry/ La Jolla, San Diego 92093-0901 ______________________________________________ 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.
