Vahid Mir - 1 year ago 79

R Question

I have this array of values:

`> df`

[1] 2 0 0 2 2 0 0 1 0 1 2 1 0 1 3 0 0 1 1 0 0 0 2 1 2 1 3 1 0 0 0 1 1 2 0 1 3

[38] 1 0 2 1 1 2 2 1 2 2 2 1 1 1 2 1 0 0 0 0 0 0 0 0 0 0 1 0 1 1 0 1 0 0 0 0 0

[75] 0 0 0 0 0 1 1 0 1 1 1 1 3 1 3 0 1 2 2 1 2 3 1 0 0 1

I want to use package boot to calculate the standard error of the data. http://www.ats.ucla.edu/stat/r/faq/boot.htm

So, I used this command to pursue:

`library(boot)`

boot(df, mean, R=10)

and I got this error:

`Error in mean.default(data, original, ...) :`

'trim' must be numeric of length one

Can someone help me figure out the problem? Thanks

Answer Source

If you are bootstrapping the mean you can do as follows:

```
set.seed(1)
library(boot)
x<-rnorm(100)
meanFunc <- function(x,i){mean(x[i])}
bootMean <- boot(x,meanFunc,100)
>bootMean
ORDINARY NONPARAMETRIC BOOTSTRAP
Call:
boot(data = x, statistic = meanFunc, R = 100)
Bootstrap Statistics :
original bias std. error
t1* 0.1088874 0.002614105 0.07902184
```

If you just input the `mean`

as an argument you will get the error like the one you got:

```
bootMean <- boot(x,mean,100)
Error in mean.default(data, original, ...) :
'trim' must be numeric of length one
```