As the number of air travelers with time on their hands increases, logic would indicate spending on retail purchases in airports would increase as well. A study by Airport Revenue News addressed the per-person spending at select airports for merchandise, excluding food, gifts, and news items. A file titled Revenues contains sample data selected from airport retailers in 2001 and again in 2004.
a. Produce a scatter plot for the per-person spending at selected airports for merchandise, excluding food, gifts, and news items, for the years 2001 and 2004. Does there appear to be a linear relationship between spending in 2001 and spending in 2004? Explain your response.
b. Calculate the correlation coefficient between the per-person spending in 2001 and the per-person spending in 2004. Does it appear that an increase in per-person spending in 2001 would be associated with an increase in spending in 2004? Support your assertion.
c. Conduct a hypothesis test to determine if a positive correlation exists between the per-person spending in 2001 and that in 2004. Use a significance level of 0.05 and assume that these figures form a random sample.