Facilities Management:Management at the The University of Texas at Austin Physical Plant is interested in reducing the average time to completion of routine work orders. The time to completion is defined as the difference between the date of receipt of a work order and the date closing information is entered. The number of labor hours charged to each work order and the cost of materials are two variables believed to be related to the time to completion of the work order. Management wants to know if there is any difference in the time to completion of work orders, on average, for different types of buildings. Buildings are classified into four types on the TCU campus: residence halls, athletic, academic, and administrative. In answering the question, take into account the possible effect of labor hours charged and materials cost. The data for a random sample of 72 work orders (chosen from a population of 11,720) are available in the worksheet entitled "WORKORD7R". The variables are as follows.

DAYS=number of days to complete each work orderHOURS=number of hours of labor charged to each work orderMATERIAL=cost of materials charged to each work order (in USD)BUILDING=1 for residence halls (RH)2 for athletic buildings (ATB)3 for academic buildings (ACB)4 for administrative buildings (ADB)