well, i don't have the answer but, a quick simulation (when the ratio of
variances is about 2) is as follows
maybe this helps in some strange way
===========
MTB > rand 10000 c1-c25;
SUBC> norm 100 5.
MTB > rand 10000 c26-c50;
SUBC> norm 100 7.07.
MTB > rstdev c1-c25, c51
MTB > rstdev c26-c50, c52
MTB > let c51=c51**2
MTB > let c52=c52**2
MTB > let c53=c52/c51
MTB > dotp c53 <<< sampling distribution of ratios of variances ....
Dotplot: C53
Each dot represents up to 95 points
.
::.
.:::.
:::::.
.::::::.
:::::::::
.::::::::::..
.::::::::::::::.............. ... . . .
+---------+---------+---------+---------+---------+-------C53
0.0 2.5 5.0 7.5 10.0 12.5
MTB > desc c53
Descriptive Statistics: C53
Variable N Mean Median TrMean StDev SE Mean
C53 10000 2.1625 1.9902 2.0945 0.9360 0.0094
Variable Minimum Maximum Q1 Q3
C53 0.4462 11.6670 1.5075 2.6281
MTB >
At 12:47 PM 5/4/01 +1000, Alan McLean wrote:
>Hi to all.
>
>Can anyone tell me what is the distribution of the ratio of sample
>variances when the ratio of population vriances is not 1, but some
>specified other number?
>
>I want to be able to calculate the probability of getting a sample ratio
>of 1 when the population ratio is, say, 2.
>
>Many thanks in advance.
>Alan
>
>
>--
>Alan McLean ([EMAIL PROTECTED])
>Department of Econometrics and Business Statistics
>Monash University, Caulfield Campus, Melbourne
>Tel: +61 03 9903 2102 Fax: +61 03 9903 2007
>
>
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_________________________________________________________
dennis roberts, educational psychology, penn state university
208 cedar, AC 8148632401, mailto:[EMAIL PROTECTED]
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