Data set 4 [Monthly share index]
Data: 25 delivery services
Variables:
x1 . . . refill time [min]
x2 . . . number of refilled units [-]
x3 . . . distance (walked by driver) [ft]
Source: D. C. Montgomery, E. A. Peck, Introduction to Linear Regression Analysis. John Wiley & Sons, New York 1982.
Task: Linear regression of x2 and x3 on x1. Investigate the influence of both independent variables.