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Re: Samples between PSPP and SPSS
From: |
Jason Stover |
Subject: |
Re: Samples between PSPP and SPSS |
Date: |
Wed, 21 Sep 2011 12:50:47 -0400 |
User-agent: |
Mutt/1.5.18 (2008-05-17) |
On Wed, Sep 21, 2011 at 10:12:39AM -0400, Andy Choens wrote:
> If I set a set to a consitent value, say 123, and create a sample in PSPP
> will it match the sample created by SPSS?
I doubt it, but can't be sure becaus the source code to SPSS is kept
secret.
> If someone
> knows which pseudo number generator is being used by PSPP and SPSS
> respectively that would also be a big help so I could
> replicate / confirm output indpenedently.
As of about 10 years ago, most of SPSS used a multiplicative
congruential random number generator. It had a period of either 2^31 -
1 or 2^32 - 1. They may still use such a generator, since changing it
would cause users' old syntax to give different answers.
PSPP uses the Mersenne Twister, which has a period of 2^19937 - 1, as
implemented in GSL. You can see the code for it in src/math/random.c.
-Jason
- Samples between PSPP and SPSS, Andy Choens, 2011/09/21
- Re: Samples between PSPP and SPSS,
Jason Stover <=
- Re: Samples between PSPP and SPSS, John Darrington, 2011/09/21
- Re: Samples between PSPP and SPSS, Andy Choens, 2011/09/21
- Re: Samples between PSPP and SPSS, Ben Pfaff, 2011/09/21
- Re: Samples between PSPP and SPSS, Andy Choens, 2011/09/21
- Re: Samples between PSPP and SPSS, Ben Pfaff, 2011/09/21
- Re: Samples between PSPP and SPSS, Andy Choens, 2011/09/22
- Re: Samples between PSPP and SPSS, Karel Novotny, 2011/09/22