Architectural firm billings. A summary of firms engaged in commercial architecture in the Indianapolis, Indiana, area provides characteristics including total annual billing in billions of dollars and the number of architects, engineers, and staff employed.4 Consider developing a model to predict total billing.
(a) Using numerical and graphical summaries, describe the distribution of total billing and the number of
architects, engineers, and staff.
(b) For each of the 6 pairs of variables, use graphical and numerical summaries to describe the relationship.
(c) Carry out a multiple regression. Report the fitted regression equation and the value of the regression
standard error s.
(d) Analyze the residuals from the multiple regression. Are there any concerns?
(e) The firm HCO did not report its total billing but employs 3 architects, 1 engineer, and 17 staff members. What is the predicted total billing for this firm?