Mean of Geometric and Negative Binomial distributions
- To: mathgroup at smc.vnet.net
- Subject: [mg24066] Mean of Geometric and Negative Binomial distributions
- From: "Gareth J. Russell" <russell at cerc.columbia.edu>
- Date: Thu, 22 Jun 2000 01:01:58 -0400 (EDT)
- Sender: owner-wri-mathgroup at wolfram.com
Dear Group,
Can anyone tell me why Mathematica returns (1-p)/p for
Mean[GeometricDistribution[p]] and n(1-p)/p for
Mean[NegativeBinomialDistribution[p]], when all sources I have to hand (such
as CRC Standard Mathematical Formulae) give these as 1/p and n/p
respectively?
The variance expressions agree with CRC, it's just the means that are
different.
Thanks,
Gareth
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Dr. Gareth J. Russell
NEW ADDRESS and E-MAIL FROM 1ST SEPTEMBER, 1999
Center for Environmental Research and Conservation
MC 5556
Columbia University
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E-mail: russell at cerc.columbia.edu
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OLD ADDRESS (AND STILL MY EMPLOYERS)
Department of Ecology and Evolutionary Biology
University of Tennessee
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