[Scipy-tickets] [SciPy] #1895: stats binom at non-integer n

SciPy Trac scipy-tickets@scipy....
Tue Apr 23 07:49:19 CDT 2013


#1895: stats binom at non-integer n
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 Reporter:  josefpktd    |       Owner:  rgommers   
     Type:  defect       |      Status:  new        
 Priority:  normal       |   Milestone:  Unscheduled
Component:  scipy.stats  |     Version:  0.12.0     
 Keywords:               |  
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Comment(by Sytse):

 The discussion you refer to is about something different: the Erlang
 distribution appears to be identical to the gamma distribution, apart from
 the fact that one of the Erlang parameters is restricted to integer
 values.
 You therefore may consider the gamma distribution as a 'continuous'
 extension of the Erlang distribution: both share the same support and the
 limit of the gamma probability density function as the parameter
 approaches an integer value is the same as the Erlang probability density
 function for this integer value.

 If  the integer value restriction to the binomial n is dropped, you
 obviously don't get such a 'continuous' extension: the resulting
 'distribution' either has no finite support (as in the binomial case), or
 its total probability is not 1, where the latter in my opinion is an
 essential property of a probability distribution.

 The slogan "practicality beats purity" sounds appealing, but is imo not a
 fair summary of the problem.

-- 
Ticket URL: <http://projects.scipy.org/scipy/ticket/1895#comment:3>
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