Seems there were some line break issues when pasting the code, trying again with a different commenting style:
#start a timer start = proc.time()[1] #set the true correllation rho = .5 #set the number of Subjects Ns = 100 #for each subject, set a number of observations in A a.No = 1:100 #for each subject, set a number of observations in B b.No = 1:100 #set the between Ss variance in condition A v.a = 1 #set the between Ss variance in condition B v.b = 2 #for each subject, set a standard deviation in A s.a.w = 1:100 #for each subject, set a standard deviation in B s.b.w = 1:100 #set the number of monte carlo experiments mce = 1e3 #set up a collector for the simulated correlations sim.r = vector(length=mce) #define a covariance matrix for use in generating the correlated data Sigma=matrix(c(v.a,sqrt(v.a*v.b)*rho,sqrt(v.a*v.b)*rho,v.b),2,2) #set up a collector for subject means in A a = vector(length=Ns) #set up a collector for subject means in B b = vector(length=Ns) #start a monte carlo experiment for(i in 1:mce){ #generate correlated ideal means for for each subject in each condition sub.means=mvrnorm(Ns,rep(0,2),Sigma) #for each subject for(s in 1:Ns){ #generate some data for A and grab the mean a[s] = mean(rnorm(a.No[s],sub.means[s,1],s.a.w[s])) #generate some data for B and grab the mean b[s] = mean(rnorm(b.No[s],sub.means[s,2],s.b.w[s])) } #store the observed correlation between A and B sim.r[i] = cor(a,b) } #show the total time this took print(proc.time()[1]-start) ______________________________________________ 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.