Re: The sum of square deviations: A THEOREM


Kevin E. Thorpe wrote:
I would have replied sooner, but with being on vacation and
spending the afternoon on the golf course, I am not online
all the time.

Anything is better than online following up on Afonso! :-)

"Luis A. Afonso" wrote:

__5__ In conclusion
We should not, in any instances (IMO), make confusion
between the Sample Variance and the UNBIASED
ESTIMATE of the Population variance - are rather different things.

I find this statement odd. The SAMPLE variance s^2 IS the
unbiased estimate of the POPULATION variance.

That is an unnecessary insistance. I had shown, repeatedly
that it doesn't matter whether one uses the UNBIASED version
of the sample variance (division by N-1) or the MLE version
of the sample variance (division by N), Afonso's statement
about SAMPLE vs POPULATION variances is ALWAYS wrong.

You found his statement odd only because he calls the MLE
form the "sample variance" rather than the (usual) unbiased
form. But that's just an irrelevant red-herring of Afonso's.

As everyone knows, he is simply WRONG, in whatever form
he chose to call the "sample variance".

Henceforth, it's up to you, Jack Tomsky (whom he called
Jack Tomson), Yurra (who he called Bob), and whoever
else sane person in this newsgroup to try to educate and
correct all of Afonso's MAJOR ERRORS. I seriously doubt
anyone will succeed.

-- Reef Fish Bob.

.

Relevant Pages

  • ANYONE who does NOT follow the 4-line example, please SPEAK UP.
    ... Obviously I DIDN'T write that horrendous English Afonso wrote, ... Let be the example Bob chose to *prove* I was wrong ... LAA> the SAMPLE variance is always <= the POPULATION variance. ...
    (sci.stat.math)
  • SIX "Is this sufficiently clear" questions for Luis A. Afonso to answer
    ... This is also IRRELEVANT to your LAAF. ... We should not, in any instances, make confusion between the Sample Variance and the UNBIASED ESTIMATE of the Population variance - are rather different things. ... Luis A. Afonso asked Kevin ...
    (sci.stat.math)
  • Re: Difference b/w Standard Deviation and Variance
    ... At least Afonso is trying to talk statistics when he made his error ... __the SAMPLE STANDARD DEVIATION is its squared root. ... IF I WANT, based on the sample items, to have an UNBIASED ESTIMATION of the POPULATION VARIANCE we must divide the sum of the squared deviations not by N but by N-1. ... an insignificant number of authors chose to define ABUSIVELY the sample variance using N-1. ...
    (sci.stat.math)
  • Re: The sample s.d. always underestimates
    ... _1__The goal is to compare the Distribution Variance with the Sample Variance. ... Afonso, can't you understand simple English as in Jack's first line ... Jack> The sample variance depends only on the sample, ...
    (sci.stat.math)
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