Posted by
Spousta Jan on
Dec 21, 2006; 3:27pm
URL: http://spssx-discussion.165.s1.nabble.com/Sample-Means-tp1072828p1072842.html
I understand your concern, Rick, but I suggested to test the two
independet subgroups against each other (students vs. non-students)
which is clearly OK if all other premises of T-test hold.
And then I proved that if these two subgroups are significantly
different, then also students vs. all people ares significantly
different regardless of the dependency, that is the test can be extended
in this way.
As I already wrote, the chi-square test is inappropriate because it does
not test differences of means but differences of shapes. And as Samir
wrote, it faces the same problem: students vs. all are not independent
:-)
Therefore I respectfully disagree with your suggestion and wish you (and
all other list members) merry Christmas and happy new Year.
Jan
-----Original Message-----
From: SPSSX(r) Discussion [mailto:
[hidden email]] On Behalf Of
Rick Bello
Sent: Thursday, December 21, 2006 3:56 PM
To:
[hidden email]
Subject: Re: Sample Means
I would respectfully disagree with Jan's suggestion of using a t-test as
the assumption of independence is violated. Although within each group
the samples are independent (each student or non-student is entered only
once) the students contribute to both groups. I would tend to agree
with Samir's suggestion of using a chi square goodness of fit test here.
Rick Bello, MD, PhD
Albert Einstein College of Medicine
New York, NY