> -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of azzza > Sent: Tuesday, October 16, 2007 9:06 AM > To: r-help@r-project.org > Subject: Re: [R] Need some help > > > > You are right, I was a bit too vague. I am trying to simulate > 1000 coin > Tosses. Then to write a code for the number of > heads/Tails.....naturally, we > would expect the proportion of heads to be 50% so the number > of heads would > be around 500. Secondly, I'm trying to look at the number of > sign changes in > 1000 tosses. The example in the book shows that the number of > sign changes > is WAY less than 50%. so I was trying to look for a code > that shows the > number of sign changes, which someone pointed out would be to use > rle(x).....my concern however is that when the rle(x) is used, the > proportion of sign changes is about 50% (around 500), which > would be logical > to expect, however, real life experiments have shown that the > number of sign > changes is actually much less than 50%. The other thing I was > trying to do > is to plot a line graph of number of sign changes versus the number of > tosses. Yes, the number of tosses should begin at zero, and > at zero coin > toss, the sign change is zero. The range of the number of > sign changes in > the Y-axis should include negative values of Y. So, for toss > number zero, > the sign change is 0, for the first toss, the sign change may > be +3 for > instance,
I guess I don't understand what you mean by "sign change". It seems to me that on any given toss there either is or there isn't a change from heads to tails (or tails to head). How then would it be possible to get a +3 sign change on the first toss? Also, I might guess as to what you mean by a negative sign change but my crystal ball is in the shop :-). Again, I would recommend that you simulate 10 coin tosses, and then by hand determine your negative and positive sign changes, and then show us the tosses, the sign changes, and the y value that you want plotted for each toss. That would at least clarify for me (if for no one else) what the issues are. Sorry I don't have any better advice at the moment, Dan Daniel J. Nordlund Research and Data Analysis Washington State Department of Social and Health Services Olympia, WA 98504-5204 ______________________________________________ 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.
