Assume that you are tutoring a student from your engineering statistics class who encounters the following statements in different sources. The first of these is: “The null hypothesis, denoted by H0, is the claim about one or more population characteristics that is initially assumed to be true” (the “prior belief” claim). The second reads: “To ask and answer questions about engineering phenomena the engineer must pose two competing hypotheses, a working hypothesis (the hypothesis to be nullified, sometimes called the null hypothesis) and an alternative hypothesis. Generally, the engineer intends to demonstrate that the data are supported by the alternative hypothesis.”
Your fellow student is nonplused, especially since the first statement appears in a statistics text and practically contradicts the second statement(s), which seems to zero in on what “null” means in a generic sense. Are the statements in conflict? What would you say to the student?