[R] Beta distribution approximate to Normal distribution

[peter dalgaard]

On 15 Sep 2015, at 15:26 , JLucke at ria.buffalo.edu wrote:

> Your question makes no sense as stated.  However, guessing at what you 
> want, you should  perhaps consider the non-central chi-square density with 
> 1 df and ncp = u/a, i.e,
> 
> rchisq(100, df=1, ncp=u/a)

Something's not right with that. Noncentral chisquare has mean df+ncp and variance 2*df + 4*ncp, which doesn't work out as anything like u and a^2. 

Other possibilities include gamma and lognormal distributions.

-pd

> 
> Joe
> 
> 
> 
> Joseph F. Lucke, PhD
> Senior Statistician
> Research Institute on Addictions
> University at Buffalo
> State University of New York
> 1021 Main Street
> Buffalo, NY  14203-1016
> 
> 
> 
> 
> 
> 
> Chien-Pang Chin <chienpang.c at gmail.com> 
> Sent by: "R-help" <r-help-bounces at r-project.org>
> 09/15/2015 06:58 AM
> 
> To
> "r-help at r-project.org" <r-help at r-project.org>, 
> cc
> 
> Subject
> [R] Beta distribution approximate to Normal distribution
> 
> 
> 
> 
> 
> 
> Hi,
> 
> I need to generate 1000 numbers from N(u, a^2), however I don't want to 
> include 0 and negative values. How can I use beta distribution approximate 
> to N(u, a^2) in R.
> 
> Thx for help
> 
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-- 
Peter Dalgaard, Professor,
Center for Statistics, Copenhagen Business School
Solbjerg Plads 3, 2000 Frederiksberg, Denmark
Phone: (+45)38153501
Office: A 4.23
Email: pd.mes at cbs.dk  Priv: PDalgd at gmail.com