Good Morning Prof. Ripley: Thanks very much for the help. I do have the Davison and Hinkley text but I continued to struggle with the proper syntax to make iteration work. The MASS package is already installed on my machine and I have the manual so I will check the example you mentioned.
Thanks again. Adam ________________________________ From: Prof Brian Ripley <rip...@stats.ox.ac.uk> Cc: r-help@r-project.org Sent: Mon, January 4, 2010 1:46:51 AM Subject: Re: [R] Assistance with boot() Package On Sun, 3 Jan 2010, Adam Carr wrote: > Good Evening R Community: > > I believe I understand the basics of using the boot() bootstrap resampling > function in the boot() package. I have not had any trouble creating a > boot.object to which I apply the boot.ci() function to calculate one or all > of the available confidence intervals. > > What I am not sure about is if this set of functions can generate more than > one confidence interval of one or all of the types available. > > I have a large data set (n=133,456) data set from which I would like to > remove random samples of different sizes and then calculate 95% confidence > intervals for the mean, 10% trimmed mean and median. I would like to > determine how often the confidence intervals generated by boot.ci() contain > the mean, 10% trimmed mean and median of the large data set. > > I have looked at some examples for using the boot() and boot.ci() functions > to generate confidence intervals for the intercept and predictive variables > from a regression model, but I do not, or cannot I suppose, determine how I > can generate more than one set of normal, basic, percentile and BCa > confidence intervals using these two functions. Well, it can be done easily. Studying the book for which 'boot' is support software would be a good start, but a hint is to look at the 'index' argument to boot.ci: basically boot() can be called with a 'statistic' which returns a vector, then boot.ci() called on each of the components of interest. There is an example in MASS (the book) on pp 225-6. > I am running R version 2.9.2 on an IBM T61 laptop. My OS is Win XP > professional SP 3, and the machine has a 1.99 GHz processor with 2.99 GB of > RAM. The version of the boot() package I am running is 1.2-41. > > Thanks in advance for taking the time to help me. > > Adam > > > > [[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. PLEASE do -- no HTML mail for a start, and please update your R. -- Brian D. Ripley, rip...@stats.ox.ac.uk Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/ University of Oxford, Tel: +44 1865 272861 (self) 1 South Parks Road, +44 1865 272866 (PA) Oxford OX1 3TG, UK Fax: +44 1865 272595 [[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.
