Chapter 13.5, Problem 13.24E

Construction Projects In a study to examine the relationship between the time required to complete a construction project and several pertinent independent variables, an analyst compiled a list of four variables that might be useful in predicting the time to completion. These four variables were size of the contract, $x_1(\text{in }\$1000\text{ unit}),$ number of workd ays adversely affected by the weather $x_2$ , number of subcontractors involved in the project $x_4$ , and a varia ble $x_3$ that measured the presence $\text{(}{x}_3=1)$ or absence $\text{(}{x}_3=0)$ of a workers’ strike during the construction. Fifteen construction projects were randomly chosen, and each of the four variables as well as the time to completion were measured.

An analysis of these data using a first-order model in $x_1,x_2,x_3$ and $x_4$ produced the following printout. Give a complete analysis of the printout and interpret your results. What can you say about the apparent contribution of $x_1$ and $x_2$ in predicting y?