Chapter 14, Problem 72PS

The owner of a moving company typically has his most experienced manager predict the total number of labor hours that will be required to complete an upcoming move. This approach has proved useful in the past, but the owner has the business objective of developing a more accurate method of predicting labor hours. In a preliminary effort to provide a more accurate method, the owner has decided to use the number of cubic feet moved and the number of pieces of large furniture as the independent variables and has collected data for 36 movers in which the origin and destination were within the borough of Manhattan in New York City and the travel time was an insignificant portion of the hours worked. The data are organized and stored in moving.

a. State the multiple regression equation.

b. Interpret the meaning of the slopes in the equation.

c. Predict the mean labor hours for moving 500 cubic feet with two large pieces of furniture.

d. Perform a residual analysis on your model and determine whether the regression assumptions are valid.

e. Determine whether there is a significant relationship between labour hours and two independent variables (the number of cubic feet moved and the number of pieces of large furniture) at the 0.05 level of significance.

f. Determine the p-values in (i) and interpret their meaning.

k. Construct a 95% confidence interval estimate of the population slope between labour hours and the number of cubic feet moved.

l. Compute and interpret the coefficients of partial determination.

m. What conclusions can you reach concerning labor hours?