The principal of a middle school claims that annual incomes

The principal of a middle school claims that annual incomes of the families of the seventh-graders at his school vary more than the annual incomes of the families of the seventh-graders at a neighboring school, which have variation described by s = $13,700. Assume that a hypothesis test of the claim has been conducted and that the conclusion of the test was to reject the null hypothesis. Identify the population to which the results of the test apply.

A. The current seventh graders at the principal’s school

B. Seventh graders’ families at the school with a standard deviation of $13,700

C. All of the families of the class of seventh graders at the principal’s school

D. All seventh graders’ families

Solution

As the claim is that the incomes of the families in his school have greater standard deviation, then that will be the alternative hypothesis.

Thus, the population here is

OPTION C: All of the families of the class of seventh graders at the principal’s school. [ANSWER]