Re: st: Logistic regression interpretation

[Michael Morrison <Morrimic@niacc.edu>]

I recommend you read Long & Freese (2006) /Regression Models for 
Categorical Dependent Variables Using Stata. It provides interpretation 
of odds, _controlling for covariates_ and ways to test your model's 
goodness of fit. Also of interest is their Spost commands.

Mike

/

On 9/21/2010 4:36 PM, Dr. Bill Westman wrote:
> Dear Listers: I have more of a stats question than a stata question,
> but here goes:
>
> A simple logistic regression was run - outcome - Survived/Non Survived
> (1/0), with Group(Treatmeant/Control -- 1/0)&  Risk(High/Low -- 1/0)
>
> The results
> ------------------------------------------------------------------------------
>         Survived | Odds Ratio   Std. Err.      z    P>|z|     [95%
> Conf. Interval]
> -------------+----------------------------------------------------------------
>      Risk |   4.790295   2.589136     2.90   0.004     1.660699    13.81763
>     group |   2.111181   .9107981     1.73   0.083     .9063649    4.917538
> ------------------------------------------------------------------------------
>
> Assuming the .10 level of significance was acceptable (for discussion purposes)
>
> Can I assume that odds of treatment survival were 2.1  times higher in
> the treatment Group for LOW risk patients?
> And for High Risk patients in the treatment group is the adds 4. 8 +
> 2.1 (or 6 times higher)?
>
> Other than test for interactions, can I run a graphs of these two groups?
>
> Can I estimate the "average" effect of Treatment across both high and
> low risk patients?  If so, how?
>
> What other tests might I wish to do in Stata?
>
> Thanks
>
> Bill
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