Question

Assuming the data is best modeled by a linear function predict the number of gallons used if she drives at an average of 62 mph A 39 gallons B 36 gallons C 51 gallons D 47 gallons

Answer 1

Linear regression

Let's graph the points of the given table, where the Speed will correspond to the x axis and the gallons to the y axis.

We have the following plot:

Let's draw a line that join the first point (20, 23) and the last point (50,35)

We have that this line is a good approximation to a linear regression of the data.

If we observe the point where x = 62 mph, we will se that y obtains a value of 40:

Then, we have that if she drives at 62 mph she will use approximately ≈40 gallons

The choice that bests fits 40 gallons is 39.

Answer: A. 39 gallons

If we verify with a calculator, we will have that the linear regression is given by the green line