A research analyst believes th a t a positive relationship exists between a firm's advertising expenditures and its sales. For 65 firms, she collects data on each firm's yearly advertising expenditures and subsequent sales. She calculates a Spearman rank correlation coefficient o f 0.45.

a. Specify the com peting hypotheses to determ ine w hether advertising and sales are correlated.

b. Assume that the sampling distribution o f rs is approxim ately normal. Calculate the value o f the test statistic and the p-value.

c. At the 5% significance level, are advertising and sales correlated? Explain.