Perhaps, we should endeavor not to provide any kind of help for such homework problems, especially to untraceable e-mail addresses (such as gmail, hotmail, yahoo and the like)? After all, conceptualizing a solution before writing R code is very much a part of the learning process, no?
Ranjan On Sun, 14 Aug 2011 17:57:38 -0500 Dennis Murphy <djmu...@gmail.com> wrote: > Hi: > > This definitely sounds like a homework problem but it's very easy to > do in R if you think about it the right way. > > (1) Generate a matrix of random numbers. This is easier than it looks, > since you can generate a long vector of random numbers and then > reshape it into a matrix. Typically, a row corresponds to a single > random sample, so that should tell you how many columns you need; the > number of samples tells you the number of rows. Type ?rpois at the R > prompt to see its help page. If necessary, also read the result of > ?matrix. > (2) See the help page of the function rowMeans(). Run it on your > matrix; it will return a vector. > (3) Plot the histogram. See ?hist > (4) Read the Posting Guide, which is linked at the bottom of this > e-mail, and pay attention to the policy on homework questions. (This > should be point (0), but I'm being pragmatic.) > > Dennis > > On Sun, Aug 14, 2011 at 6:16 AM, maggy yan <kiot...@googlemail.com> wrote: > > my data looks like this: > > > > PM10 Ref UZ JZ WT RH FT WR > > 1 10.973195 4.338874 nein Winter Dienstag ja nein West > > 2 6.381684 2.250446 nein Sommer Sonntag nein ja Süd > > 3 62.586512 66.304869 ja Sommer Sonntag nein nein Ost > > 4 5.590101 8.526152 ja Sommer Donnerstag nein nein Nord > > 5 30.925054 16.073091 nein Winter Sonntag nein nein Ost > > 6 10.750567 2.285075 nein Winter Mittwoch nein nein Süd > > 7 39.118316 17.128691 ja Sommer Sonntag nein nein Ost > > 8 9.327564 7.038572 ja Sommer Montag nein nein Nord > > 9 52.271744 15.021977 nein Winter Montag nein nein Ost > > 10 27.388416 22.449102 ja Sommer Montag nein nein Ost > > 11 6.460829 4.486329 ja Winter Samstag nein nein Süd > > 12 5.937690 10.247768 ja Sommer Sonntag nein nein Nord > > 13 14.004685 5.155790 nein Winter Sonntag nein nein Nord > > 14 12.244333 7.063825 ja Sommer Mittwoch nein ja Nord > > 15 35.195541 12.148438 nein Winter Montag nein nein Ost > > . > > . > > . > > . > > til 200 > > now I should illustrate the Central limit theorem with my data. I need to > > make 80 times the arithmetic means of each of the 100 poisson distributet > > random numbers with an expected value 7. > > the hint says I need a metrices first which includes all of the 8000 values. > > but I have no idea where the 8000 values are and how to make the matrices. > > please help me > > > > [[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. > > > > > > ______________________________________________ > 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.
