Re: a novice asks about ANOVA

On 29 Aug 2005 16:38:14 -0700, zabed@xxxxxxxxxxx wrote:

> Thanks Luis but its still not lear the relationship of P with H values?
> My original question was what if P gets smaller?

The p-value describes the F-value, with its associated
degrees of freedom, precisely. It is the value of the
"cumulative distribution function" (CDF) of the F test.

It sounds to me as if you need to do a lot more
preparation, in the form of scanning some texts in
statistics, before attempting anything serious.


>
> One more thing, I changed 4 values out of 60 (3 data in 20 groups) and
> it drastically changed the whole scenario!!!! Just by tweaking 4 values
> I can get Ftest smaller than Fcrit!!!!!

You can probably do that by tweaking one value sufficiently.

>
> Does it indicate some kinds of weakness in ANOVA analysis?

I'd call it a "characteristic" of ANOVA -- ANOVA measures
squared deviations from means, and how they are
partitioned.

Hope this helps.

--
Rich Ulrich, wpilib@xxxxxxxx
http://www.pitt.edu/~wpilib/index.html
.