calculation of 90% CI for continuous variable in clinical endpoint studies [General Sta­tis­tics]

posted by ElMaestro  – Denmark, 2017-11-20 21:41 (2404 d 21:09 ago) – Posting: # 17993
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Hi GM,

❝ How can we will calculate 90% CI for ratio of means of untransformed continuous variable using PROC GLM in SAS.


Why is it that you want the endpoint to be untransformed?
Statistically normal distributions are wonderful because any two normal distributions added (= subtracted) will yield a new normal distrution. But try and divide them and you are facing a mathematical challenge that is in no way straightforward to deal with.
If you want to do a parametric CI on a ratio then the only way forward that I know of is a transformation one way or another so that the endpoint can reasonably be assumed normal.

So I am sorry that I cannot answer your question in the way you have asked it. Having said this I am of the impression that you don't really need a 90% CI for a ratio of untransformed means.

Pass or fail!
ElMaestro

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