Hi Just a copy :-) Answers please! Anyway, did my answer resolve your issue?
Petr From: Clive Nicholas [mailto:cliveli...@googlemail.com] Sent: Wednesday, November 14, 2012 4:07 AM To: PIKAL Petr Cc: r-help@r-project.org Subject: Re: [R] Bootstrapping issues Thank you for your answer - I will consult the help file to see if it has anything to useful to say by way of a solution - but I don't understand why you accused me of shouting. I merely pasted in the R output which contained the heading of the results in block letters: I honestly didn't know that this now constituted shouting. I don't believe it does. Unless, of course, you objected to my emphasising of certain words _like this_. I rather think you'll find that this, too, does not contravene any sort of list 'netiquette' - it's commonly found on other listservs - and that perhaps you're being rather too sensitive in response. C On 13 November 2012 12:53, PIKAL Petr <petr.pi...@precheza.cz<mailto:petr.pi...@precheza.cz>> wrote: Hi From: Clive Nicholas [mailto:cliveli...@googlemail.com<mailto:cliveli...@googlemail.com>] Sent: Tuesday, November 13, 2012 3:12 AM To: PIKAL Petr Cc: r-help@r-project.org<mailto:r-help@r-project.org> Subject: Re: [R] Bootstrapping issues Petr Pikal replied: [...] > The following works > > results <- boot(data=test, statistic=bs, R=1000, A~B+C+D+C*D) > Actually it does not work either Correct, but I _did_ get it to work shortly before my initial post (sorry for not showing it, but I didn't save the output - silly me). What seems to happen is that I successfully run the version that _does_ work, which I then follow up with successful calls to -plot(results,index=#)- and -boot.ci<http://boot.ci>(results,type="bca",index=#)-, then I follow up with the unsuccessful version of the code, which won't run and produces the error, but when I go back to run the original code, this too produces the same error. This, to me at least, is very weird behaviour for R. > results <- boot(data=test, statistic=bs, R=1000, A~B+C+D+C*D) Error in data[indices, ] : incorrect number of dimensions > I am not sure but I suspect your bs function expects some indices vector and it is somehow not in accordance with your data. This code, using different simulated data _does_ run, however: > mytest<-data.frame(Y=rnorm(500, mean=60, sd=1), X1=sample(c("AAA", "BBB", > "CCC", "DDD", "None", NA), size=500, replace=TRUE), X2=sample(c(0.88, 0.99, > 1.43, 1.22, 1.1), size=500, replace=TRUE), X3=sample(c("Yes", "No"), > size=500, prob=c(0.6,0.4), replace=TRUE)) > bs <- function(formula, data, indices) { + mytest <- data[indices,] + fit <- lm(formula, data=mytest) + return(coef(fit)) + } > results <- boot(data=mytest, statistic=bs, R=1000, formula=Y~X1+X2+X3) Hm. Maybe the difference is in using formula. > results <- boot(data=test, statistic=bs, R=1000, A~B+C+D+C*D) >From help page, the fourth parameter is called sim and shall be character >vector. See below. > results <- boot(data=mytest, statistic=bs, R=1000, Y~X1+X2+X3) Error in data[indices, ] : incorrect number of dimensions > results <- boot(data=mytest, statistic=bs, R=1000, formula=Y~X1+X2+X3) > results ORDINARY NONPARAMETRIC BOOTSTRAP Call: boot(data = mytest, statistic = bs, R = 1000, formula = Y ~ X1 + X2 + X3) Bootstrap Statistics : original bias std. error t1* 59.67822240 -0.0060177161 0.29491879 t2* 0.09745349 0.0004995554 0.15627776 t3* 0.24210280 -0.0047317673 0.15018019 t4* -0.03399254 -0.0046603446 0.15884994 t5* 0.15302117 -0.0038503464 0.14045470 t6* 0.15040121 0.0074829413 0.24225957 t7* 0.18454691 -0.0003127565 0.09321305 > <snip> Answers please! Do not shout, please. I presented an answer and if you consulted help page you could find out what I also found out. Regards Petr Clive Nicholas (clivenicholas.posterous.com<http://clivenicholas.posterous.com> [Please DO NOT mail me personally here, but at <clivenicho...@hotmail.com<mailto:clivenicho...@hotmail.com>>. Please respond to contributions I make in a list thread here. Thanks!] "My colleagues in the social sciences talk a great deal about methodology. I prefer to call it style." -- Freeman J. Dyson -- Clive Nicholas (clivenicholas.posterous.com<http://clivenicholas.posterous.com>) [Please DO NOT mail me personally here, but at <clivenicho...@hotmail.com<mailto:clivenicho...@hotmail.com>>. Please respond to contributions I make in a list thread here. Thanks!] "My colleagues in the social sciences talk a great deal about methodology. I prefer to call it style." -- Freeman J. Dyson [[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.
