Hi You're correct. The problem is in "statistic" not in boot.
However it is not clear for me that the definition of t states it must have allways the same number of dimensions. What it says is that it will be a bootstrap replicate of statistic. In my linear model I use factors and the number of coefficients might change, if the bootstrap data set omits one or more levels. My understandment is that the result of "statistic" is still a bootstrap replicate no matter the number of dimensions. Anyway, thanks for being helpfull. Regards EJ On Thu, 2003-01-16 at 15:02, [EMAIL PROTECTED] wrote: > That's not a problem in boot, but a problem in your usage of it. > > On 16 Jan 2003, Ernesto Jardim wrote: > > > Hi > > > > I found the problem (I hope:). > > > > In "boot" a data.frame with the expected results from "statistic" is > > created, "t.star", wich has dim[[1]]=sum(R), the number of replicates, > > and dim[[2]]=lt0, the length of the output of statistic using the > > original data. > > > > t0 <- statistic(data, original, ...) > > lt0 <- length(t0) > > t.star <- matrix(NA, sum(R), lt0) > > > > However when fitting the "lm" with different sets of data, it might > > happen that the result of "statistic" is not of the same length has with > > the original data. That's when > > > > for (r in 1:sum(R)) t.star[r, ] <- statistic(data, i[r,], ...) > > > > fails, because its not able to replace the complete row of t.star. > > > > So "statistic" shall guarantee that all the outputs are of the same > > length. > > > > Something you might want to had to "boot" documentation. > > It's already there: > > statistic: A function which when applied to data returns a vector > containing the statistic(s) of interest. > > t: A matrix with `R' rows each of which is a bootstrap replicate > of `statistic'. > > Where does it say that the statistic(s) of interest can change by > replicate? -- Ernesto Jardim <[EMAIL PROTECTED]> Marine Biologist Research Institute for Agriculture and Fisheries Lisboa, Portugal Tel: +351 213 027 000 Fax: +351 213 015 948 ______________________________________________ [EMAIL PROTECTED] mailing list http://www.stat.math.ethz.ch/mailman/listinfo/r-help
