A taxi company is interested in the relationship between mileage, measured in miles per gallon, and the age of cars in its fleet. The 12 fleet cars are the same make and size and in good operating condition as a result of regular maintenance. The company employs both male and female drivers, and it is believed that some of the variability in mileage may be due to differences in driving techniques between the groups of drivers of opposite gender. In fact, other things being equal. women tend to get better mileage than men. Data are generated by randomly assigning the 12 cars to five female and seven male drivers and computing miles per gallon after 300 miles. The data appear in Table P-11.

a. Construct a scatter diagram with Y as the vertical axis and X, as the horizontal axis. Identify the points corresponding to male and female drivers, respectively.