Absolutely nothing to do with the CLT. If X_1, ..., X_n are i.i.d.
N(mu, sigma^2) then
Xbar is N(mu,sigma^2/n). Exactly. No asymptotics, no approximations,
no CLT.
cheers,
Rolf Turner
On 10/26/13 20:17, Tsjerk Wassenaar wrote:
> Hi :)
>
> Try this with other distributions too... And then search for 'central limit
> theorem'.
>
> Cheers,
>
> Tsjerk
>
>
> On Fri, Oct 25, 2013 at 4:48 PM, Kramer, Christian <
> christian.kra...@uibk.ac.at> wrote:
>
>> Hi there,
>>
>> I have found a strange behavior in R that puzzles me - maybe it is a bug
>> or a basic scientific misunderstanding of mineâEUR¦ anyway, I would highly
>> appreciate some feedback on this, since I did not find anything on the
>> internet.
>>
>> I am trying to simulate a t-distribution by adding up normally distributed
>> numbers:
>>
>> a <- (rnorm(1000) + rnorm(1000) + rnorm(1000) )/3
>>
>> However, when I look at the distribution using
>>
>> qqnorm(a)
>>
>> this looks more like a normal distribution than a t-distribution:
>>
>> b <- rt(1000,2)
>> qqnorm(b)
>>
>> Is this to be expected? Or is this an issue with the random number
>> generator or something else?
>>
>> Thanks a lot for replies in advance,
>> Christian
>>
>> --------------------------------------------
>> Dr. Christian Kramer
>> Theoretical Chemistry
>> University of Innsbruck
>> Innrain 82
>> A-6020 Innsbruck
>> Tel.: +43 512 507 57103
>> Homepage: http://homepage.uibk.ac.at/~c72448/kramer.html
>> Email: christian.kra...@uibk.ac.at
>>
>> ______________________________________________
>> R-help@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.
>>
>
>
>
>
> ______________________________________________
> R-help@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.
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