[R] Output for Boot function in Car package

[John Fox]

Dear David and Dan,

Yes, the column labelled "bootMed" is the median of the bootstrapped values. As it turns out, this isn't documented in the help for the car package, nor in the on-line appendix on bootstrapping from the CAR book. It's easy, however, to print car:::summary.boot to see the straight-forward things that it does.

I hope this helps,
 John

------------------------------------------------
John Fox, Professor
McMaster University
Hamilton, Ontario, Canada
http://socserv.mcmaster.ca/jfox/

On Sat, 14 Jun 2014 15:08:21 -0700
 David Winsemius <dwinsemius at comcast.net> wrote:
> 
> On Jun 14, 2014, at 1:15 AM, Dan Hughes wrote:
> 
> > Dear users,
> > 
> > Can anyone help with a rather simplistic question about the interpretation
> > of output using the Boot ( ) function in the Car package?
> > 
> > I am trying to bootstrap a simple univariate linear regression in order to
> > look at the bootstrap regression coefficients e.g.
> > 
> > mod1 <- lm (y~x)
> > mod1.b <- Boot(mod1, R=999)
> > summary (mod1.b)
> > 
> > This returns output like this:
> > 
> >                  R      original       bootBias      bootSE       bootMed
> >  (Intercept) 999   5.365528   -8.0960e-05   0.0501306   5.365241
> >  x              999   0.032211    7.3683e-05   0.0029743   0.032158
> > 
> > I'm having trouble finding out what "bootMed" means. If 'original' is the
> > non-bootstrapped regression coefficient, is bootMed the bootstrapped
> > regression coefficient?
> > 
> > I presume this is a frighteningly simple question for regular car package
> > users, but I can't seem to find an explanation what this means.
> 
> I'm not a regular or even an intermittent user of `car` but offhand I would suspect it is the median. 
> 
> Do read the Posting Guide, 
> and the help page for Boot and the tutorial that is linked from that help page,  
> and please learn to post in plain text.
> 
> > 
> > Best wishes
> > 
> > Dan Hughes
> > 
> > 	[[alternative HTML version deleted]]
> 
> -- 
> 
> David Winsemius
> Alameda, CA, USA
> 
> ______________________________________________
> R-help at 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.