Question

How does the speed at which you drive affect your fuel economy? To find out, researchers drove a compact car for 200 miles at speeds ranging from 35 to 75 miles per hour. From their data, they created the model Fuel Efficiency = 32 - 0.1 Speed and created this residual plot:

Answer 1

Explanation:

The formula i.e.

Fuel Efficiency = 32-0.1*speed

represents that the efficiency on very lower speeds will be affected very minor as the multiple of 0.1 which will be subtracted from 32 will be small value.

Secondly, as per attached full question and graph plot, it is clear that up to 26.5 predicted (mpg), the trend of Residual (mpg) is increasing while after 26.5, it starts to decrease nearly linearly.

It's slop can be find out by two point formula i.e.

slope = m =(y2-y1)/(x2-x1)

=(1-2.5)/(27.5-27)

=(-1.5)/(0.5)

=-3

negative sign shows decreasing trend of second half plot