The logistics department within a firm in the Twin Cities area wants to understand its cost drivers better. Since labor hours (y) form a crucial component of the department's cost, the goal is to identify factors that affect labor hours.

The logistics department has collected sample data for 20 weeks (in collaboration with the accounting department). The data provided in the enclosed Excel file includes information on labor hrs (y), pounds shipped in lbs (x1), % of units shipped by truck (x2), and average shipment weight in lbs (x3).

a) Fit a multiple regression equation in excel linking labor hrs (y) to pounds shipped (x1), % of units shipped by truck (x2), and average shipment weight (x3). Provide the equation below based on your excel output.

b) Estimate and interpret the 99% Confidence Interval for the coefficient ₃ in the above equation. (3 points)

c) Using the multiple linear regression equation obtained in a), what is the average labor hrs for a week in which 7100 pounds were shipped with 25% of the units being shipped by truck and the average shipment weight being 30 lbs.(2 points)