Umm, yes, what you had makes a lot of sense. How would I represent that in a plot of the number of sign changes in the to Y axis, and the toss number (from 0 to 1000) in the x-axis?
jholtman wrote: > > You might want to check out 'rle'. This will give you the 'lengths' > of runs of the same value and therefore when the value changes (sign > change?) you can see how often: > >> x <- sample(c(-1,1), 1000, TRUE) >> rle(x) > Run Length Encoding > lengths: int [1:483] 2 2 1 4 3 1 1 1 1 2 ... > values : num [1:483] -1 1 -1 1 -1 1 -1 1 -1 1 ... > > Here was a sample of 1000, and there were 483 changes between the > samples. Is this what you are looking for? > > On 10/15/07, azzza <[EMAIL PROTECTED]> wrote: >> >> >> Quite helpful indeed. Greatly appreciated. >> Another problem I had was trying to simulate an example from my book. >> Simulating 1000 coin tosses, and finding the frequency of sign changes. >> So >> how will we plot this using R? (frequency of sign changes in Y axis) >> >> >> >> >> Daniel Nordlund wrote: >> > >> >> -----Original Message----- >> >> From: [EMAIL PROTECTED] >> [mailto:[EMAIL PROTECTED] >> >> On Behalf >> >> Of azzza >> >> Sent: Sunday, October 14, 2007 10:21 PM >> >> To: r-help@r-project.org >> >> Subject: [R] Need some help >> >> >> >> >> >> Hi! >> >> I'm taking a course that requires some programming background, but I'm >> a >> >> complete novice in the field. >> >> >> >> when asked to generate a list of 20 uniform random numbers, is it >> alright >> >> if >> >> I put in >randu, and just copy-paste the first 20 numbers?? Or is >> there, >> >> as >> >> I suspect, a better way of calling out exactly 20 uniform random >> >> numbers?? >> >> >> > See ?runif >> > >> > rand_nums <- runif(20) >> > >> >> I'm also unable to solve the following problem: >> >> We know that on average 30% of the customers who enter a store make a >> >> purchase. Suppose 200 >> >> people enter the store today. Run a simulation to see how many >> purchases >> >> we >> >> will have today. >> >> >> > see ?sample >> >> number_of_purchases <- sum(sample(c(0,1), 200, prob=c(.70, .30), >> >> replace=TRUE)) >> > >> > Hope this is helpful, >> > >> > Dan >> > >> > Daniel Nordlund >> > Bothell, WA USA >> > >> > ______________________________________________ >> > 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. >> > >> > >> >> -- >> View this message in context: >> http://www.nabble.com/Need-some-help-tf4624513.html#a13214128 >> Sent from the R help mailing list archive at Nabble.com. >> >> ______________________________________________ >> 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 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. > > -- View this message in context: http://www.nabble.com/Need-some-help-tf4624513.html#a13216156 Sent from the R help mailing list archive at Nabble.com. ______________________________________________ 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.
