[R] boot question

[Achim Zeileis]

On Thu, 1 Apr 2004 17:19:55 -0500  Morris, Jeffrey [OCDUS] wrote:

> What in the world am I missing??

The help page?

As help(boot) tells you:

statistic: <snip>
          In all other cases 'statistic'
          must take at least two arguments.  The first argument passed
          will always be the original data. The second will be a vector
          of indices,
           <snip>

So I would think you want to do:

R> mymean <- function(x, index) mean(x[index])
R> boot(x, mymean, R = 20)

ORDINARY NONPARAMETRIC BOOTSTRAP


Call:
boot(data = x, statistic = mymean, R = 20)


Bootstrap Statistics :
    original     bias    std. error
t1*   0.1775 0.03224225   0.1302358

hth,
Z

> > x<-rnorm(20)
> 
> > mean(x)
> [1] -0.2272851
> 
> > results<-boot(x,mean,R=5)
> 
> > results[2]
> $t
>            [,1]
> [1,] -0.2294562
> [2,] -0.2294562
> [3,] -0.2294562
> [4,] -0.2294562
> [5,] -0.2294562
> 
> Jeff Morris
> Ortho-Clinical Diagnostics
> A Johnson & Johnson Co.
> Rochester, NY
> Tel: (585) 453-5794
> 
> 
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> 
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