Re: st: Recovering cell values from odds ratios

[Maarten Buis <maartenlbuis@gmail.com>]

On Tue, May 31, 2011 at 2:06 PM, King, Carina wrote:
> Thanks for replying, but I think I'm a bit confused, I've attached the example I'm using:
>
> Cases: 218
> Controls: 14748
> Total: 14966
>
> Risk factor:      OR:    p:       case exposed(a): control exposed (b): case unexposed(c): control unexposed(d):
>
> Unconsciousness   3.54   0.77973   48              3248                 170                       11500
> Age >65 years     1.69   0.62825   81              5483                 137                       9265
> Female gender     1.66 0.62406 82                 5544                 136                       9204
>
> With the method you describe, the p for each comes out as shown above and consequently the numbers in each group. BUT when I then checked by recalculating the odds ratio from the numbers given, they all equal 1. What am I missing?  Thank you!

I don't understand what you did your example. What is p and where did
it come from? Which part of those numbers did you compute and which
were given. How did you do the computations?  Where is the baseline
odds?

Generally, I think your example contains too many variables. The best
strategy for problems like these is to start with an easy example,
i.e. one variable, work till you understand that and than complicate
matters till you get what you want.

-- Maarten

--------------------------
Maarten L. Buis
Institut fuer Soziologie
Universitaet Tuebingen
Wilhelmstrasse 36
72074 Tuebingen
Germany


http://www.maartenbuis.nl
--------------------------

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