But this seems to me to be equivalent to sample(rep(1:20, 5), 20), which I previously suggested and was pointed out to be wrong....
Giovanni On Wed, 2011-03-02 at 11:05 -0700, Vokey, John wrote: > On 2011-03-02, at 4:00 AM, [email protected] wrote: > > > Hello there, > > > > I have a problem concerning bootstrapping in R - especially focusing on the > > resampling part of it. I try to sum it up in a simplified way so that I > > would not confuse anybody. > > > > I have a small database consisting of 20 observations (basically numbers > > from 1 to 20, I mean: 1, 2, 3, 4, 5, ... 18, 19, 20). > > > > I would like to resample this database many times for the bootstrap process > > with the following conditions. Firstly, every resampled database should > > also include 20 observations. Secondly, when selecting a number from the > > above-mentioned 20 numbers, you can do this selection with replacement. The > > difficult part comes now: one number can be selected only maximum 5 times. > > In order to make this clear I show you a couple of examples. So the > > resampled databases might be like the following ones: > > > > (1st database) 1,2,1,2,1,2,1,2,1,2,3,3,3,3,3,4,4,4,4,4 > > 4 different numbers are chosen (1, 2, 3, 4), each selected - for the > > maximum possible - 5 times. > > > > (2nd database) 1,8,8,6,8,8,8,2,3,4,5,6,6,6,6,7,19,1,1,1 > > Two numbers - 8 and 6 - selected 5 times (the maximum possible times), > > number 1 selected 4 times, the others selected less than 4 times. > > > > (3rd database) 1,1,2,2,3,3,4,4,9,9,9,10,10,13,10,9,3,9,2,1 > > Number 9 chosen for the maximum possible 5 times, number 10, 3, 2, 1 chosen > > for 3 times, number 4 selected twice and number 13 selected only once. > > > > ... > > > > Anybody knows how to implement my "tricky" condition into one of the R > > functions - that one number can be selected only 5 times at most? Are > > 'boot' and 'bootstrap' packages capable of managing this? I guess they are, > > I just couldn't figure it out yet... > > > > Thanks very much! Best regards, > > Laszlo Bodnar > > Laszlo, > Create a vector consisting of 5 of each number. Then, for each sample, > scramble the order of the items in the vector, and select the first 20. > > > -- > Please avoid sending me Word or PowerPoint attachments. > See <http://www.gnu.org/philosophy/no-word-attachments.html> > > -Dr. John R. Vokey > > ______________________________________________ > [email protected] 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. ______________________________________________ [email protected] 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.
