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Date: Fri, 17 Jun 2016 20:41:05 +0000 (UTC)
From: "Karl D. Gierach (JIRA)" <jira@apache.org>
To: issues@commons.apache.org
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Subject: [jira] [Commented] (MATH-1373) In LogNormalDistribution.java, it
 appears shape & scale are reversed/mis-labelled.
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archived-at: Fri, 17 Jun 2016 20:41:12 -0000


    [ https://issues.apache.org/jira/browse/MATH-1373?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15336901#comment-15336901 ] 

Karl D. Gierach commented on MATH-1373:
---------------------------------------

I will come up with a patch based on github:  http://git-wip-us.apache.org/repos/asf/commons-math.git
Also, it appears the parameters are reversed in getNumericalVariance() as well.

Sound OK?

Thanks,
Karl

> In LogNormalDistribution.java, it appears shape & scale are reversed/mis-labelled.
> ----------------------------------------------------------------------------------
>
>                 Key: MATH-1373
>                 URL: https://issues.apache.org/jira/browse/MATH-1373
>             Project: Commons Math
>          Issue Type: Bug
>    Affects Versions: 3.6.1
>            Reporter: Karl D. Gierach
>            Priority: Minor
>   Original Estimate: 1h
>  Remaining Estimate: 1h
>
> When I compute the logshape and log scale based on the formulas on wikipedia's lognormal distribution page that use empirical mean and variance, I found that the getNumericalMean() method was not returning the empirical mean.
> However, upon just trying to reverse the shape and scale parameters in the constructor proved to fix the problem, and the object then returns the correct empirical mean.


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