1. The manager of Jensen Tire aAuto feels that the amount of the distribution for engine maintenance in the company is inuenced by the length of use of the engine every week. To prove the problem, the manager took samples from 1D machines and measured the use of the machine and the amount of maintenance costs, obtained the following data: Based on this data: a. Which are the dependent variables and independent variables of the data? b. Create a regression model of the data. c. Test whether the length of use of the machine affects maintenance costs by using a = 1%. d. If a new machine has been in use for 15 months, what is the maintenace cost prediction of the machine? 2. The following is income data (in millions} of men and women who have the same level of education. Using a = 0.05 tested whether there was a difference in male and female income if it was assumed that both had different population variances. m 3.05 3.55 4.52 4.22 3.32 Female 4.45 3.54 4.29 4.n5| 4.99 5.53] 4.35 4.32! 3.58