Thanks for the suggestion, Mike. We do have data for other zones -- I am looking at flu rate and sample size. Thanks again -- I really appreciate it!
Date: Fri, 24 Oct 2014 17:08:21 -0700
From:
[hidden email]To:
[hidden email]Subject: Re: chi square but very disparate sample sizes
Just to develop the point made below a little bit: I noticed
that the larger sample had the larger percentage of flu cases.
If there were more "populations" or groups, one might want
to see if there is a correlation between flu rate and sample
size. If such a result was obtained, it could mean that larger
groups, for whatever reason, would have higher flu rates
(perhaps because of increased opportunities for infection, etc.).
If there is additional data, this might be something to look at.
-Mike Palij
New York University
[hidden email]
----- Original Message -----
On Friday, October 24, 2014 6:43 PM, Richard Ristow wrote:
> At 02:28 PM 10/22/2014, sgthomson99 wrote:
>
>>If Population A is 4000 patients and there are 3.2% with the flu, and
>>Population B is 53500 patients and 3.9% have the flu, is the
>>difference in prevalence of the flu significant or not?
>
> One more consideration: the chi-square is based on the assumption that
> different individuals' contracting the flu are statistically
> independent events.
>
> I don't know details of influenza epidemiology, but it is a readily
> transmissible infection, and a difference in rates could be due to
> random events that affect a number of people together: for example, a
> cluster around one case who'd been out and around and infected a good
> many other people.
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