[R] bootstrap help

[Marek Janad]

data<-data.frame(x=rnorm(49), y=rnorm(49))
t(sapply(1:50,function(i){colMeans(data[sample(nrow(data),size=nrow(data),replace=TRUE),])}))


r-help at r-project.org

2009/12/7 casperyc <casperyc at hotmail.co.uk>:
>
> Hi there,
>
> i think that's not what i was aiming for...
>
> i was aked to
>
> Generate 50 Bootstrap samples and corresponding estimates
>
> if i do data[sample(nrow(data),size=50,replace=TRUE),]
> it will give me a table of 50 rows ( 50 sets of x and y)
> then how do i estimate the mean? ( mean was esitmated by the bar{x}/bar{y} )
>
> i mis undertood that too.
> but now, i think what i actually need is
>
> 50 sets of this kind (49 rows) of tables from bootstrapping
> so that i can have 50 different 'bar{x}/bar{y}' s
> then to estimate the mean...
>
> Thanks.
>
> casper
>
>
>
> Ben Bolker wrote:
>>
>> casperyc <casperyc <at> hotmail.co.uk> writes:
>>
>>> I have 49 pairs in my data.frame 'data'
>>>
>>> x    y
>>> 76   80
>>> ...  ...
>>>
>>> how do I get a bootstrap sample of size n=50?
>>>
>>
>> data[sample(nrow(data),size=50,replace=TRUE),]
>>
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>> and provide commented, minimal, self-contained, reproducible code.
>>
>>
>
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>
> ______________________________________________
> R-help at r-project.org mailing list
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> and provide commented, minimal, self-contained, reproducible code.
>



-- 
Marek