[R] A somewhat off the line question to a log normal distrib

Thomas Lumley tlumley at u.washington.edu
Thu Dec 2 17:06:58 CET 2004

On Thu, 2 Dec 2004 Ted.Harding at nessie.mcc.ac.uk wrote:

> Hmm, perhaps you should think again! If X and Y have log-normal
> distributions (mathematically exactly), then (X+Y)/2 does not
> (mathematically) have a log-normal distribution -- still less
> the arithmetic mean of some 30 such variables. So one wonders
> what the basis of his "explanation" was.

The original poster's boss did not (as far as we know) claim that the 
measurements were either independent or identically distributed.  While 
the problem would be simpler if they were, there is no guarantee that the 
answer would be remotely relevant.


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