11.13 Automobile fuel economy. Government regulations require automakers to give the city and highway gas mileages for each model of car. Table 11.2 gives the combined highway and city mileages (miles per gallon) for 31 model year 2015 sedans. Make a stemplot of the combined gas mileages of these cars. What can you say about the overall shape of the distribution? Where is the center (the value such that half the cars have better gas mileage and half have worse gas mileage)? Some of these cars are electric and the reported milage is the electric equivalent. These cars have far higher mileage. How many electric cars are in this data set?