Rachel Keyes <rkeyes87 <at> hotmail.com> writes: > > > I am new to R and Im some trouble with the following question... Generate 100 standard normal N(0,1) samples > of size 100, X1(k),...,X100(k) where k=1,...,100 (The k is and indicie in brackets) Calculate the sample > mean for each sample. For each sample mean Xbark the 0.95-confidence interval for the mean mew=0 is given > by... Ik= ( Xbark plus or minus 1.96/10) Find the number of intervals such that 0 does not belong to Ik. How > many of them do you expect to see? Well so far I have come up with... N<-100; Nsamp<-100 > A<-matrix(rnorm(N*Nsamp,0,1),ncol=Nsamp) means<-apply(A,2,mean) However I have no idea what I am > doing and no idea if that even makes sense. Any help would be greatly appreciated as I have no experience of > statistical software whatsoever. Thanks in Advance. Rachel >
This sounds an awful lot like a homework problem. Can you convince us not by giving us a little more context? I will say that you seem to have made a pretty good start. A hint is that if you have a logical condition, sum(condition) will count the number of cases. For example, sum(means>0) will count the number of positive means. ?abs and ?">" may help too. By the way, I think that's supposed to be "mu" and not "mew". Ben Bolker ______________________________________________ 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.