Data regarding fuel efficiency of an 18-wheel truck were collected. the graph shows the correlation between the average speed above 40 miles per hour (in miles per hour) and the money spent on gas (in dollars): image of a scatter plot with average speed on the x axis and money spent on fuel on the y axis with points 1 comma 2, 3 comma 2 and one half, 5 comma 5, 7 comma 7, 9 comma 10, 11 comma 15, and 12 comma 17 estimate the average rate of change from x = 5 to x = 9. 4 −4 0.8 1.25