Terry and Associates: The Time to Deliver Medical Kits   Terry and   Associates is a specialized medical testing center in Denver, Colorado. One   of the firm’s major sources of revenue is a kit used to test for elevated   amounts of lead in the blood. Workers in auto body shops, those in the lawn   care industry, and commercial house painters are exposed to large amounts of   lead and thus must be randomly tested. It is expensive to conduct the test,   so the kits are delivered on demand to a variety of locations throughout the   Denver area.   Kathleen   Terry, the owner, is concerned about setting appropriate costs for each   delivery. To investigate, Ms. Terry gathered information on a random sample   of 50 recent deliveries. Factors thought to be related to the cost of   delivering a kit were:   Prep The time in minutes between when the customized order is phoned into the   company and when it is ready for delivery.   Delivery The actual travel time in minutes from Terry’s plant to the customer.   Mileage The distance in miles from Terry’s plant to the customer.   Develop a   multiple linear regression equation that describes the relationship between   the cost of delivery and the other variables.   Do these   three variables explain a reasonable amount of the variation in the dependent   variable?   Estimate   the delivery cost for a kit that takes 10 minutes for preparation, takes 30   minutes to deliver, and must cover a distance of 14 miles.   Test to   determine if one or more regression coefficient differs from zero. Also test   to see whether any of the variables can be dropped from the analysis. If some   of the variables can be dropped, rerun the regression equation until only   significant variables are included.   Write a   brief report interpreting the final regression equation  

     Sample   Number Cost Prep Delivery Mileage   1 $32.60  10 51 20   2 23.37 11 33 12   3 31.49 6 47 19   4 19.31 9 18 8   5 28.35 8 88 17   6 $22.63  9 20 11   7 22.63 9 39 11   8 21.53 10 23 10   9 21.16 13 20 8   10 21.53 10 32 10   11 $28.17  5 35 16   12 20.42 7 23 9   13 21.53 9 21 10   14 27.55 7 37 16   15 23.37 9 25 12   16 17.1 15 15 6   17 27.06 13 34 15   18 15.99 8 13 4   19 17.96 12 12 4   20 25.22 6 41 14   21 24.29 3 28 13   22 22.76 4 26 10   23 28.17 9 54 16   24 19.68 7 18 8   25 25.15 6 50 13   26 20.36 9 19 7   27 21.16 3 19 8   28 25.95 10 45 14   29 18.76 12 12 5   30 18.76 8 16 5   31 $24.29  7 35 13   32 19.56 2 12 6   33 22.63 8 30 11   34 21.16 5 13 8   35 21.16 11 20 8   36 19.68 5 19 8   37 18.76 5 14 7   38 17.96 5 11 4   39 23.37 10 25 12   40 25.22 6 32 14   41 27.06 8 44 16   42 21.96 9 28 9   43 22.63 8 31 11   44 19.68 7 19 8   45 22.76 8 28 10   46 21.96 13 18 9   47 25.95 10 32 14   48 26.14 8 44 15   49 24.29 8 34 13   50 24.35 3 33 12