It seems to me that you are asking for: > hhh <- 0.1 > sum(dbinom(x=0:50,size=500,prob=hhh)) [1] 0.5375688
> You can use 'sample' and 'rle': > >> x <- sample(c("H","T"), 500, replace=TRUE, prob=c(.95, .05)) >> as.data.frame(unclass(rle(x))) > lengths values > 1 12 H > 2 1 T > 3 10 H > 4 1 T > 5 5 H > 6 2 T > 7 26 H > 8 1 T > 9 17 H > 10 1 T > 11 54 H > 12 1 T > 13 23 H > 14 1 T > 15 7 H > 16 1 T > 17 2 H > > > On Thu, Oct 9, 2008 at 1:16 PM, Harvey <[EMAIL PROTECTED]> wrote: >> Can someone recommend a method to answer the following type of question: >> >> Suppose I have a coin with a probability hhh of coming up heads (and >> 1-hhh >> of coming up tails) >> I plan on flipping the coin nnn times (for example, nnn = 500) >> What is the expected probability or frequency of a run of rrr heads* >> during >> the nnn=500 coin flips? >> Moreover, I would probably (excuse the pun) want the answer for a range >> of >> rrr values, for example rrr = 0:50 >> >> Of course I am more interested in an analytical solution than a monte >> carlo >> simulation solution. >> >> Thanks in advance, >> >> Harvey >> >> * OR "a run of rrr heads or more ..." >> >> [[alternative HTML version deleted]] >> >> ______________________________________________ >> 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. >> > > > > -- > Jim Holtman > Cincinnati, OH > +1 513 646 9390 > > What is the problem that you are trying to solve? > > ______________________________________________ > 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. > ______________________________________________ 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.