An engineer examines the relationship between the w eight of a car and its average miles per gallon (MPG). For a sample of 100 cars, he calculates a Spearman rank correlation coefficient of - 0.60.
a. Specify the competing hypotheses in order to determine whether a negative relationship exists between a car's weight and its average MPG.
b. Assume that the distribution of rs is approximately normal. Calculate the value of the test statistic and the p-value.
c. At the 5% significance level, are the variables negatively related? Explain.