Sensitivity of term? [Regulatives / Guidelines]

posted by mittyri – Russia, 2017-05-02 20:29 (2640 d 07:10 ago) – Posting: # 17294
Views: 30,259

Hi Helmut and ElMaestro,

Helmut answered to the question directed to me more accurate than I can ;-)

❝ The idea behind the Group-by-Treatment interaction is that the T/R in one group is different from the other (i.e., we have collinearity with a “hidden” variable). Therefore, simulate a group of subjects with T/R 0.95 and another one with T/R 0.95–1 (CV ad libitum). Merge them to get a “study”. Run model 1 and check the p-value of the Group-by-Treatment interaction. With the simple model you should expect T/R 1.


seems to be reasonable, but I do not see why the power is low?
So if our hypothesis is that the power is low, we need to reject H0 that power is high, in another words to prove that sensitivity of this term to deviations is low.
By the way if the power of this term is low, some other should be high, right? which one? :confused:

❝ ❝ M+H: FDA are also fitting subject as fixed even when using the random statement in PROC GLM. Some of them just have not realised it :-)


❝ True.


AFAIK PHX knows only one model where subject is fitted as fixed term when placed to the variance structure, that's conventional model. In all other cases LinMix will switch to the mixed modeling.

❝ ❝ (and by the way: Which denominator in F did you apply; within or between?)


❝ Numerator DF = Groups – 1

❝ Denominator DF = Subjects – 2 × Groups


Yes, the results are the same for complete data (mixed vs glm)

Kind regards,
Mittyri

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