Hypothesis testing 65
In order to test such assertions on the basis of samples of the distributions
involved, it is also necessary to formulate alternative hypotheses. To distin-
guish these from the o riginal assertions, the latter are traditionally called null
hypotheses. Thus we might be interested in testing the simple null hypothesis
µ = 0 against the composite alternative hypothesis µ 6= 0. An appropriate
sample function for deciding whether or not to reject the null hypothesis in
favor of its alternative is referred to as a test statistic, often denoted by the
symbol Q. An appropria te test procedure will partition the possible realiza-
tions of the test statistic into two subsets: an acceptance region for the null
hypothesis and a rejection ...