Re: Assumptions for another Fisher's exact test??

From: Gaj Vidmar (gaj.vidmar_at_mf.uni-lj.si)
Date: 12/29/04 

Date: Wed, 29 Dec 2004 13:11:37 +0100

A few useful links:

1. first of all, and it migh well be enough, see
http://www.med.uio.no/imb/stat/two-by-two/manual.html
(start with Definitions and methods section, then calculate online)

2. if you'll want more on exact unconditional tests, go to R.Berger's page
at
http://www4.stat.ncsu.edu/~berger/tables.html

3. for something new (by R.Darlington), try
http://www.psych.cornell.edu/Darlington/twobytwo/tbt.htm
and http://www.psych.cornell.edu/Darlington/lukoff.htm
and then http://stats.brianlukoff.com/

(actually, I'm posting the last three links in the hope to hear some opinion
from the experts in this NG - the poster just needs something "standard"
and "the way it is usually done")

Regards,

Gaj Vidmar
Univ. of Ljubljana, Fac. of Medicine, Inst. of Biomedical Informatics

"Bevin Keen" <bevin.keen@afit.edu> wrote in message
news:uj8mhczhpxvt@legacy...
> Hi there! I am looking to use Fisher's exact test to test a
> hypothesis for my Masters thesis. I saw that other contingency table
> approaches require certain assumptions to be met in terms of a
> 'multinomial experiment' and the expected cell counts need to be
> greater than 5 in order to use the chi squared distribution.
>
> Since the Fisher's exact test is based on a hypergeometric
> distribution, are there certain assumptions that must be met?? What
> are they? I have a few Nonparametric texts, but they don't really
> address the assumptions for this test.
>
> I am including a the hypothesis that I am trying to test:
>
> For purposes of this research question, the hypotheses being tested
> are:
> H0 : p1 = p2, the response rate(Yes) for series B is equal to the
> response rate(Yes) for series C
> HA : ñ1 < p2, the response rate (Yes) for series B is less than the
> response rate (Yes) for series C.
> Where:
> P1= the probability that a question will result in a yes response for
> a B series evaluation
> P2= the probability that a question will result in a yes response for
> a C series evaluation
>
> [I have a 2 x 2 contingency table; the rows are time of the inspection
> (B series or C series) and the columns are Response (Yes or No) to
> inspection questions.