Question

Timothy downloaded 10 files to his computer. The scatter plot below shows the relationship between the size of the file and the amount of time needed to download.

The graph titled Downloading files shows Time in seconds on y-axis and size in megabytes on x-axis. There are dots at (5, 30), (5, 40), (10, 37), (10, 50), (20, 50), (22, 57). (25, 75), (30, 75), (35, 87), and (37, 75).

To represent the data, Timothy drew a line through the points (0,50) and (40,75). Which statement explains why his line is not the line of best fit for the data?

A.
Most of the data points lie below Timothy’s line.

B.
Timothy’s line is more vertical than it should be, and most of the points are too far away from the line.

C.
Most of the data points lie above Timothy’s line.

D.
Timothy’s line is more horizontal than it should be, and most of the points are too far away from the line.

Answer 1

A. Most of the data points lie below Timothy’s line.

Explanation: For the line through (0,50) and (40,75) the predicted y-values are higher than the actual y-values for 6 of the 10 points, so most points lie below his line. A line of best fit should balance the points above and below it.