Re: Negative Binomial – SPSS Bug (?)

Posted by Alex Reutter on Sep 11, 2012; 12:59pm
URL: http://spssx-discussion.165.s1.nabble.com/Negative-Binomial-SPSS-Bug-tp5715014p5715018.html

Hi Frank,

The negative binomial distribution has two fairly common parameterizations; the one you mention below, and the one Statistics uses.  In the one Statistics uses, x (quant) is the number of trials needed (including the last trial) before k (thresh) successes are observed.  In the one you mention below, x is the number of failures, x is the number of failures before k successes are observed.

See http://pic.dhe.ibm.com/infocenter/spssstat/v21r0m0/topic/com.ibm.spss.statistics.help/syn_transformation_expressions_random_variable_distribution_functions.htm for more details on the negative binomial and all of the other distributions in Statistics.

Cheers,
Alex