13.24 ● Consider the accompanying data on x 5 research and development expenditure (thousands of dollars) and y 5 growth rate (% per year) for eight different industries.

x 2024 5038 905 3572 1157 327 378 191 y 1.90 3.96 2.44 0.88 0.37 20.90 0.49 1.01

a. Would a simple linear regression model provide useful information for predicting growth rate from research and development expenditure? Use a .05 level of significance.

b. Use a 90% confidence interval to estimate the average change in growth rate associated with a $1000 increase in expenditure. Interpret the resulting interval.