Alternative hypothesis, planning

Power. The power is the probability of concluding that the alternative hypothesis is true given that it is in fact true. It depends on the statistical test being employed, the size of that test, the nature and variability of the observations obtained and the size of the trial. It also depends on the alternative hypothesis. In practice there is no single alternative h3fpothesis, so a reference alternative based on a clinically relevant difference is usually employed. The power of a trial is a useful concept when planning the trial but has little relevance to the interpretation of its results. (Caution not all statisticians agree with this last statement.)... 

One randomized trial in which patients with STEMI received therapy with GP Ilb/IIIa blockade alone or GP Ilb/IIIa blockade -i- reduced-dose fibrinolysis with a planned early invasive strategy has been reported the Bavarian Revascularization Alternatives (BRAVE) Trial. The principal hypothesis in this trial was that upstream combination therapy with reduced-dose flbrinolytics + GP nb/IIIa blockade -i- primary PCI would result in smaller scintigraphic infarct size when compared with... 

According to this hypothesis, the planned execution of the program, in the sense of selection of the path of development and the path of differentiation, is thus based on the principle of testing the situation. Because of their structure, in the tests (the possibility of which was discussed above) one "input determines one of only two alternative "outputs." Life may use more complicated tests requiring more than one input. 

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