Marv Johnson, city manager of Filkburg, Virginia, wants to develop a better understanding of the factors that influence vehicle maintenance and costs. Mr. Johnson has data on 100 vehicles in the city’s vehicle fleet. The dependent variable is the annual maintenance cost per vehicle (MCOST). The independent variables include total vehicle mileage (TMILE), a dummy variable coded 1 for emergency service vehicles and coded 0 for all other types of vehicles (VTYPE), and the total number of days the vehicle was in use over the year (TDAYS). Assist Mr. Johnson by generating a regression equation using these data. What substantive conclusions can be reached about factors that affect vehicle maintenance costs?