Looking at the frequency chart, the modal class interval is 15 cm ≤ h < 16 cm as there are 5 pieces of data in this class. Image caption, The time it takes 20 people to run 100 m is recorded.

Each piece of data is put into the correct class interval, so 14 is counted in the 10–14 class interval. Image caption, To complete the grouped frequency chart, the tallies can be added up and ...