[R] Please help with one problem

Greg Snow Greg.Snow at imail.org
Fri Dec 17 17:39:12 CET 2010


The clt.examp function in the TeachingDemos package shows the effect of sample size on approximate normality for 4 different distribution of which the uniform distribution is one.  This may do what you want, or you could start with that code and modify it to do what you want.

If not then try better explaining what you want or what your actual question is.

-- 
Gregory (Greg) L. Snow Ph.D.
Statistical Data Center
Intermountain Healthcare
greg.snow at imail.org
801.408.8111


> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-
> project.org] On Behalf Of diavolo_vam
> Sent: Thursday, December 16, 2010 11:13 AM
> To: r-help at r-project.org
> Subject: [R] Please help with one problem
> 
> 
> It is interesting to graph the distribution of the standardized average
> as n
> increases. Do this when the Xi are
> uniform on [0; 1]. Look at the histogram when n is 1, 5, 10 and 25. Do
> you
> see the normal curve taking shape?
> (A rule of thumb is that if the Xi are not too skewed, then n > 25
> should
> make the average approximately
> normal. You might want
> > f=function(n,a=0,b=1) {
> mu=(b+a)/2
> sigma=(b-a)/sqrt(12)
> (mean(runif(n,a,b))-mu)/(sigma/sqrt(n))
> }
> where the formulas for the mean and standard deviation are given. )
> 
> 
> Thank you very much!
> --
> View this message in context: http://r.789695.n4.nabble.com/Please-
> help-with-one-problem-tp3091392p3091392.html
> Sent from the R help mailing list archive at Nabble.com.
> 
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