Data regarding fuel efficiency of an airliner were collected. the graph shows the correlation between the distance traveled (in thousands of miles) and the altitude (in thousands of feet):
image of a scatter plot with distance traveled on the x axis and altitude on the y axis with (2,2), (3,10), (5,15), (10,20), (15,15), (18,10), and (19,2)
estimate the average rate of change from x = 15 to x = 19.
a. -3.25
b. 4
c. -4
d. -0.31