Question

These times, in seconds, were recorded in eight 20-yard dash attempts: 3.5, 2.9, 2.9, 3.4, 3.0, 2.8, 3.1, and 2.8. Which representation is best for comparing exact times?

A stem and leaf plot. The stems are 2, 3. The first column of leaves are 8, 0. The second column of leaves are 8, 1. The third column of leaves are 9, 4. The fourth column of leaves are 9, 5. Key: 3 line 1 = 3.1.
A line graph has attempts on the x-axis and seconds on the y-axis. Attempt 1, 3.5; attempt 2, 2.9; attempt 3, 2.9; attempt 4, 3.4; attempt 5, 3.0; attempt 6, 2.8; attempt 7, 3.1; attempt 8, 2.8.
A line plot. The are 0 marks above 1, 0 marks above 2, 4 marks above 3, and 4 marks above 4.

Answer 1

The stem-and-leaf plot. It preserves every original time (in sorted order) so you can read and compare the exact values. The line graph connects points (which can mislead) and the described line plot only shows counts, not the individual times.