Posted by
Rich Ulrich on
Feb 24, 2011; 9:57pm
URL: http://spssx-discussion.165.s1.nabble.com/appropriate-statistical-method-needed-tp3397707p3399287.html
First, look at the literature. You will look bad if you ignore a great
solution that has been published.
Second, you need an expert to tell you what outcomes are worst,
among the sort of patterns that you observe. Yes/No for "always
in the range" is about as simple and direct as you can get, but it
ignores a lot of variation. And it is pretty useless if every patient
has some excursions outside the min-max range.
What would you say about "The worst 5 (5... 15... 30... 100... ?)
seconds" of data, for any patient?
If you are expected to provide all the numerical reduction of the
data, you might find it useful to ask your expert(s) to provide a
blind rating (no knowledge of which group) to the outcomes series,
using three or more categories like [hazardous/ so-so/ safe] .
Then you use those ratings to discover numerical rules.
--
Rich Ulrich
Original post
> Date: Wed, 23 Feb 2011 13:03:44 -0800
> From:
[hidden email]> Subject: appropriate statistical method needed
> To:
[hidden email]>
> For a Phase II drug trial an appropriate statistical method is sought.
>
> The following Background:
>
> In a research on the acidity of gastric juice during cardiopulmonary bypass
> surgery a drug has been used and tested for efficacy.
>
> During the entire operation the acidity of gastric juice should remain in a
> non-hazardous area. Neither the pH value should be too high nor too low.
> Maximum and minimum limits are given.
>
> The sample was relatively small. Patients were randomly assigned to two
> groups of 20 persons each group. One group did not receive the drug, the
> other group did. The 40 operations lasted different lengths. Every second a
> probe of the stomach pH was measured. There are therefore 40 time series of
> different lengths of pH values.
>
> Question: It is to be examined whether the pH values could be stabilized due
> to the drug for the entire duration of the operation within the safe area.
> The effectiveness compared with the control group without drug is to be
> demonstrated.
>
> Which procedure, which method would be in question here?
>