A researcher selects a sample from a population with a mean of µ = 40 and administers a treatment to the individuals in the sample.If the treatment is expected to decrease scores,which of the following is the correct statement of the null hypothesis for a one-tailed test? A)µ 20 B)µ 40 D)µ

Question

A researcher selects a sample from a population with a mean of µ = 40 and administers a treatment to the individuals in the sample.If the treatment is expected to decrease scores,which of the following is the correct statement of the null hypothesis for a one-tailed test? A)µ > 20 B)µ < 45 C)µ > 40 D)µ < 80

Quizplus · Accepted Answer

The null hypothesis represents the status quo. In this case, the status quo is that the population mean is 40. If the treatment is expected to decrease scores, we would be interested in a one-tailed test that tests the hypothesis that the population mean is greater than 40. The correct statement of the null hypothesis for a one-tailed test is therefore:

H0: µ ≤ 40

Since we are testing whether scores will decrease, we are looking for evidence that the population mean is less than 40, which is the alternative hypothesis. Thus, the correct choice is C, which is the negation of the alternative hypothesis:

H0: µ ≥ 40

A Researcher Selects a Sample from a Population with a Mean