http://spssx-discussion.165.s1.nabble.com/chi-square-but-very-disparate-sample-sizes-tp5727676p5727688.html
Thank you, Art.
These numbers are actual patient data from a huge health care database. One is a small zone, and one is a big one. I do have case by case data on every patient in each zone.
I was concerned about just the sample sizes being so big for the one and so much smaller (albeit still relatively large) for the other population -- and that being the likely reason behind any statistically significant result I might find.
I'd thought I remembered seeing a paper awhile ago that tried to deal with a similar situation by taking the prevalences and just assuming n=100 and comparing the prevalences using a z test for proportions.
Since posting my question the other day, I have kept on reading and am thinking I should go with a z test for proportions and use the actual data, no assuming n=100 -- but to put a caveat on the results saying that they are significant likely due to the large but very disparate sample sizes, but that the clinical significance is the real issue. Is a difference of .7% meaningful clinically? Probably not.
Susan
Date: Fri, 24 Oct 2014 07:41:11 -0700
From:
[hidden email]To:
[hidden email]Subject: Re: chi square but very disparate sample sizes
Please describe your situation in more detail.
Are these samples?
Are these the actual populations you want to discuss?
Do you have case by case data on every member of the populations?
What are the definitions of the populations of interest?
How did you gather your data?
Art Kendall
Social Research Consultants
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