Sales and Marketing Management determined the "effective buying income" (EBI) of the average household in a state. Can the EBI be used to predict retail sales per household in the store-group category "eating and drinking places"?
a. Use the data for 13 states given in the table below to find the least squares line relating retail sales per household (y) to average household EBI (x).
b. Plot the least squares line, as well as the actual data points, on a scatter plot.
c. Based on the graph, part b, give your opinion regarding the predictive ability of the least squares line.
d. Find a 95% confidence interval for the slope of the line.
e. Use the results, part d, to assess the adequacy of the straight-line model.

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Average Household Buying Income ($) ( per household) Retail Sales: Eating and Drinking Places 9 State Connecticut New Jersey Michigan Minnesota Florida South Carolina Mississippi Oklahoma Texas Colorado Utah California Oregon 60,998 63,853 46,915 44,717 42.442 37,848 34.490 34,830 44,729 44,571 43,421 50,713 40,597 2,553.8 2.154,8 2,523.3 2,278.6 2,475.8 2358.4 1.538.4 2,063.1 2.363.5 3,214.9 2.653,8 2,215.0 2.144.0