An independent mail delivery service wants to study factors thataffect the daily gas usage of its delivery trucks. Using datacollected from different trucks on various days, a company analystuses a software to fit a regression model of the form=y+52.3+?8.9x14.1x2+5x30.09x4 , where =y volume of gasoline used(in gallons) =x1 weight of truck (in tons) =x2 tire pressure (inpsi, pounds per square inch) =x3 weight of initial package load (inhundreds of pounds) =x4 total distance driven while deliveringpackages (in miles) Answer the following questions for theinterpretation of the coefficient of x1 in this model. Holding theother variables fixed, what is the average change in daily fuelused for each additional ton that a truck weighs? gallon(s) Is thischange an increase or a decrease? increase decrease
