Assume that the distribution of the differences is mound-shaped and symmetrical. At the 1% level of signifi cance, test the claim that the population mean of the differences is positive.

(a) Check Requirements Is it appropriate to use a Student’s t distribution for the sample test statistic? Explain. What degrees of freedom are used?

(b) State the hypotheses.

(c) Compute the sample test statistic.

(d) Estimate the P-value of the sample test statistic.

(e) Do we reject or fail to reject the null hypothesis? Explain.

(f) Interpretation What do your results tell you?