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From Tim O'Brien <tobr...@discursive.com>
Subject Re: [math] Priorities, help needed
Date Wed, 21 May 2003 18:27:08 GMT
On Wed, 21 May 2003, Mark R. Diggory wrote:

> I hadn't thought of that. muli*=0 is also very detrimental to this 
> calculation as well. Would it be logical that if the value is 0.0 that 
> it gets excluded from the divison/multiplication?

Well, if the geometric mean depends on the product of all values and the 
set of values contains a zero value, I'd say that the result should be 
zero.  Think of the following situations, would the geometric mean of a 
set of 8 zero values be 1.0?  Geometric mean is always <= arithmetic mean, 
I'd say if it depends on a product it should reflect the product.

> 
> if(discard!=0)
>     mutli/=discard;
> 
> if(value != 0)
>     multi*=discard;
> 
> But if n < window then n still gets incremented. This is basically 
> treating 0 = 1 in nature. I'm not sure if its numerically kosher to do.
> 
> Thus maybe we see the weakness of the Geometric Mean.
> -Mark
> 
> 
> Tim O'Brien wrote:
> > On Wed, 21 May 2003, Mark R. Diggory wrote:
> > 
> >>multi/=discard;
> > 
> > 
> > That doesn't work.  Once you've introduced a value 0.0, there is no way to 
> > divide out a zero.
> > 
> > 
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> 

-- 
----------------------
Tim O'Brien
Evanston, IL
(847) 863-7045
tobrien@discursive.com



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