Re: F-test for comparing variances?


Art Kendall wrote:
This usually comes up in an intro course in the context of a between
groups t-test. The two group t-test is a special case of oneway
analysis of variance, which is a special application of ordinary
regression. It is an approach to testing whether the residuals (errors)
are homogeneous. Later you should be introduced to better methods for
testing this.

variance (a) is by convention the larger of the two variances under
consideration, so it does not "happen" to be larger.

The last two-line statement by Art Kendall is INCORRECT.

For reasons WHY it is incorrect and reasons WHY that should
NEVER be assumed, see the explanations in sci,.stat.math on
Art Kendall's same post.

-- Reef Fish Bob.

.

Relevant Pages

  • Re: F-test for comparing variances?
    ... Art Kendall wrote: ... groups t-test. ... variance is by convention the larger of the two variances under ... That is why the tabulation of the percentile of any F table follows ...
    (sci.stat.math)
  • Re: F-test for comparing variances?
    ... This usually comes up in an intro course in the context of a between groups t-test. ... The two group t-test is a special case of oneway analysis of variance, which is a special application of ordinary regression. ... We stick with the p/u/p represented by H0, until we have sufficient reason to believe otherwise. ... IMHO, it is unfortunate that terms like status quo, default, current, or presumed are not often enough associated with the "null" hypothesis. ...
    (sci.stat.edu)
  • Re: F-test for comparing variances?
    ... groups t-test. ... variance is by convention the larger of the two variances under ... Keeping H0 means that the [status quo, default, current, presumed] ... until we have sufficient reason to believe ...
    (sci.stat.math)