RE: chi square but very disparate sample sizes

Posted by sgthomson99 on Oct 24, 2014; 8:45pm
URL: http://spssx-discussion.165.s1.nabble.com/chi-square-but-very-disparate-sample-sizes-tp5727676p5727691.html

Many thanks for your help, David.
 
Susan
 

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Date: Fri, 24 Oct 2014 12:34:22 -0700
From: [hidden email]
To: [hidden email]
Subject: Re: chi square but very disparate sample sizes

Your instincts are wrong. You can't change the data. Incidentally, you
can also use a z test for the difference of proportions. It should
give you results that are similar to the chi-square test David
Greenberg, Sociology Department, New York University

On Wed, Oct 22, 2014 at 2:28 PM, sgthomson99 <[hidden email]> wrote:

> Hi everyone,
>
> I need advice.  I'm working with a big dataset.
>
> 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?
>
> The clinic managers are saying use chi square 2x2 table, and then the
> prevalences are hugely significantly different.  Just in my opinion because
> of the big sample size difference.
>
> I'm being conservative and saying with such hugely different sample sizes,
> it's better to use 3.2/100 versus 3.9/100 so like a z test for proportions
> for the comparison -- and it's not significant.
>
> Any suggestions greatly appreciated.
>
> Susan
>
>
>
> --
> View this message in context: http://spssx-discussion.1045642.n5.nabble.com/chi-square-but-very-disparate-sample-sizes-tp5727676.html
> Sent from the SPSSX Discussion mailing list archive at Nabble.com.
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