A hardware store keeps records of the strength of lawn mower engines and their fuel usage. The scatter plot shows a line of fit, and the table shows the residuals.

A scatter plot titled Lawn Mowers has x-axis labeled Engine Horsepower going from 0 to 28 in increments of 2 and y-axis labeled Fuel Usage (in gallons per hour) going from 0 to 3 in increments of 0.25. The graph contains ordered pairs 6,0.5 and 7,0.75 and 10,0.75 and 11,1 and 15,2 and 16,1 and 20,1.25 and 25,1.5. A line of fit is sketched through ordered pairs 7,0.75 and 22,1.5.


Horsepower of Engine Fuel Usage (in gallons per hour) Residual
6 0.5 –0.207
7 0.75 –0.007
10 0.75 –0.157
11 1 0.043
15 2 0.844
16 1 –0.206
20 1.25 –0.156
25 1.5 –0.155

Part A: What is the real-world interpretation of the strength and direction of association?

Part B: Which ordered pair is an outlier? How would the strength and direction change if the outlier were removed? Explain your reasoning.