Suppose Consumer Reports would like to investigate the relationship between the battery life (in hours) and the screen size (in diagonal inches) of a laptop computer. The following table shows a random sample of eight laptops and the battery life and corresponding screen size of each. These data can also be found in the Excel file battery life.xlsx.

Battery Life Screen Size Battery Life Screen Size 3.6 15.6 3.1 14.0 3.7 17.3 4.1 13.3 4.2 14.5 4.5 11.6 4.0 12.1 3.9 13.1

a. Calculate the Spearman rank-order correlation coefficient.

b. Using a = 0.01, perform a hypothesis test to determine if the population rank correlation coefficient is less than zero.

AppendixLO1