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Subject: Re: Comments of latest SSDF list - Nine basic questions

Author: Roy Eassa

Date: 13:18:10 06/04/02

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On June 04, 2002 at 16:08:25, Dann Corbit wrote:

>On June 04, 2002 at 16:06:55, Roy Eassa wrote:
>
>>On June 04, 2002 at 14:58:49, Dann Corbit wrote:
>>
>>>On June 04, 2002 at 14:13:43, Rolf Tueschen wrote:
>>>
>>>>I just saw your article. Could you add your opinion about how SSDF actually has
>>>>shown that computer strength is on a normal distribution? For weeks now or
>>>>better years I say it is not. It's a pity, but without that explanation you
>>>>invested so much precious time for nothing! I will answer in detail after your
>>>>explanation.
>>>
>>>SELECT int(rating/100), count([Rating]/100)
>>>FROM SSDF
>>>GROUP BY int([Rating]/100);
>>>
>>>Expr1000	Expr1001
>>>14	2
>>>15	12
>>>16	12
>>>17	23
>>>18	21
>>>19	22
>>>20	17
>>>21	25
>>>22	23
>>>23	18
>>>24	20
>>>25	18
>>>26	15
>>>27	5
>>>
>>>Happy explaining.
>>
>>
>>Just an observation: that's no bell curve.
>
>It's a pedagogic example of a platykurtotic bell curve.


OK, that sent me scurrying to a search engine.

"Kurtosis:
A measure of the extent to which observed data fall near the center of a
distribution or in the tails. A kurtosis value less than that of a standard,
normal distribution indicates a distribution with a fat midrange on either side
of the mean and a low peak-a platykurtotic distribution. A kurtosis value
greater than that of a normal distribution indicates a high peak, a thin
midrange, and fat tails. The latter, a leptokurtotic distribution, is common in
observed price, rate, and return time series data."


Does this mean it still IS a normal distribution?  (It has 2 fairly large peaks
and one smaller one, from what I can tell.)

I also found this:

"The standard normal density has the familiar shape of the Bell Curve."

Which is what I had been thinking when I posted the comment about this not being
a bell curve.



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