# [Rd] bug in rbinom? (PR#1190)

**viele@ms.uky.edu
**
viele@ms.uky.edu

*Sun, 2 Dec 2001 01:27:55 +0100 (MET)*

Full_Name: Kert Viele
Version: 1.3
OS: Windows ME and 2000
Submission from: (NULL) (65.6.218.65)
Hello! Thanks for all your efforts on R. They are appreciated!
I was simulating the central limit theorem in class,
but found that repeated use of
mean(rbinom(100000,500,0.4))
resulted in values less than 200 (the expected mean), for example
>* mean(rbinom(100000,500,0.4))
*[1] 199.0294
>* mean(rbinom(100000,500,0.4))
*[1] 199.1077
>* mean(rbinom(100000,500,0.4))
*[1] 199.0668
and so on.
I did this 1000 times and found the results to be distributed
approximately N(199.0787,s=0.036). The standard deviation
is pretty accurate, but the mean is significantly off from 200.
Thanks for any help! (including telling me my mistakes!)
- Kert Viele
Assistant Professor of Statistics
University of Kentucky
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