R help - Jul 2011 - Extracting components from a 'boot' class output in R

Dear R user,

I used the following to do a bootstrap.

>bootObj<-boot(data=DAT, statistic=Lp.est,
R=1000,x0=3)

I have the following output from the above bootstrap. How
can I extract  components of the output.
For example, how can I extract the std.error?

> bootObj
 
ORDINARY NONPARAMETRIC BOOTSTRAP
 
Call:
boot(data = DAT, statistic = Lp.est, R = 1000, x0 = 3)
 
Bootstrap Statistics :
      original        bias              std. error
t1*  794.9745 -0.6666341    4.042099

Any help is greatly appreciated.

Thank you 


Sarath Banneheka

	[[alternative HTML version deleted]]

Sarath,

Maybe someone can show a direct access to the statistic. One way to
get around is to access 't' component of the boot object which
contains individual estimates. so you can extract standard error by

sqrt(var(bootObj$t))

Weidong Gu

On Fri, Jul 22, 2011 at 11:36 AM, Sarath Gamini Banneheka
<banneheka at yahoo.com> wrote:
> Dear R user,
>
> I used the following to do a bootstrap.
>
>
>>bootObj<-boot(data=DAT, statistic=Lp.est,
> R=1000,x0=3)
>
> I have the following output from the above bootstrap. How
> can I extract? components of the output.
> For example, how can I extract the std.error?
>
>
>> bootObj
>
> ORDINARY NONPARAMETRIC BOOTSTRAP
>
> Call:
> boot(data = DAT, statistic = Lp.est, R = 1000, x0 = 3)
>
> Bootstrap Statistics :
> ????? original??????? bias????????????? std. error
> t1*? 794.9745 -0.6666341??? 4.042099
>
> Any help is greatly appreciated.
>
> Thank you
>
>
> Sarath Banneheka
>
> ? ? ? ?[[alternative HTML version deleted]]
>
>
> ______________________________________________
> 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.
>
>

Do
  names(bootObj)
to find out what the components are, and use $ or [[ to extract
components.
Do
  help(boot)
for a description of components of the object (look in the Value section).

That is general advice in R, applying to all kinds of objects -
boot, and many other functions such as lm(), return lists with
a class added, and you can operate on the object as a list using
names(), $, etc.

Tim Hesterberg
>Dear R user,
>
>I used the following to do a bootstrap.
>
>
>>bootObj<-boot(data=DAT, statistic=Lp.est,
>R=1000,x0=3)
>
>I have the following output from the above bootstrap. How
>can I extract? components of the output.
>For example, how can I extract the std.error?
>
>
>> bootObj
>
>ORDINARY NONPARAMETRIC BOOTSTRAP
>
>Call:
>boot(data = DAT, statistic = Lp.est, R = 1000, x0 = 3)
>
>Bootstrap Statistics :
>????? original??????? bias????????????? std. error
>t1*? 794.9745 -0.6666341??? 4.042099
>
>Any help is greatly appreciated.
>
>Thank you
>
>
>Sarath Banneheka