----- Original Message -----
From: <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Monday, October 16, 2000 4:24 PM
Subject: Re: questions on hypothesis
> In article <[EMAIL PROTECTED]>,
> > Chris: That's not what Jerry means. What he's saying is that if
> > your sample size is large enough, a difference may be statistically
> > significant (a term which has a very precise meaning, especially to
> > the Apostles of the Holy 5%) but not large enough to be practically
> > important. [A hypothetical very large sample might show, let us say,
> > that a very expensive diet supplement reduced one's chances of a heart
> > attack by 1/10 of 1%.]
>
> Firstly, I think we can thank publication pressures for the church of
> the Holy 5%. I go with Keppel's approach in suspending judgement for mid
> range significance levels (although we should do this for nonsignificant
> results anyway as they are inherently indeterminant).
-----------------------------------------
The 5% is a historical arifact, the result of statistics being invented
before electronic computers were invented.
The work in the early 1900's was severely restricted by the fact that
computations of the cummulative probability distribution involved tedious
paper and pencil calculations, and later on the use of mechanical
calculators. Available tables only gave the values for 5% and in some cases
1%. R.A. Fisher in his publications consistently referred to values well
below 1% as being "convincing". To illustrate the fundamental test methods,
he had to rely on available tables and chose 5% in most of his examples.
However he did not consider 5% as being "scientifically convincing".
DAH
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