We expect a car’s highway gas mileage to be related to its city gas mileage (in mpg). Data for all 1209 1209 vehicles in the government’s 2016 Fuel Economy Guide give the regression line highway mpg = 7.903 + ( 0.993 × city mpg )
(a) What is the slope of this line? (Enter your answer rounded to three decimal places.)

slope:

What does the numerical value of the slope tell you?