Re: st: analysis of continuous gestational age

[Ron�n Conroy <rconroy@rcsi.ie>]

On 30 M�rta 2007, at 16:29, Ali Khashan wrote:

> Dear all,
> I am using a very large dataset (N=1.3m) to analyse the effect of a  
> categorical
> variable on gestational age (continuous variable). I used linear  
> regression
> (regress) but as you would probably expect the residuals are not  
> normally
> distributed. I used qreg but the results do not look right.
>
> Could anyone tell me what is the best analysis for continuous  
> gestational
> please.
You need to tell us more about the data. Gestational age at delivery  
will follow one sort of distribution, while gestational age recorded  
at, say, ultrasound clinics will follow a multimodal distribution  
that reflects the recommended schedule of clinic visits.

If you have gestational age worked out from ultrasonography, this can  
be in days, which gives you a different data structure to the one you  
get from clinical notes, which is usually in whole weeks.

So we can't say yet, but some more information may help.

=========
Ron�n Conroy
Royal College of Surgeons in Ireland
rconroy@rcsi.ie
+353 (0) 1 402 2431
+353 (0) 87 799 97 95
http://www.flickr.com/photos/ronanconroy




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