On 2011-03-02, at 4:00 AM, r-help-requ...@r-project.org 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 ______________________________________________ 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.
