Paper 4 · cumulative frequency distribution
The table below shows the masses of 200 students measured to the nearest kg. | Mass (kg) | Number of students | | --- | --- | | 46-50 | 20 | | 51-55 | 60 | | 56-60 | 56 | | 61-65 | 35 | | 66-70 | 19 | | 71-75 | 10 | Using upper class boundaries, what is the cumulative number of students with mass 60.5 kg or less?
A80
B171
C190
D136
Explanation: Cumulative frequencies at the upper class boundaries are 20 (50.5), 80 (55.5), 136 (60.5), 171 (65.5), 190 (70.5), 200 (75.5). Stopping one class boundary early gives 80, and going one or two class boundaries too far gives 171 or 190; the correct cumulative total up to 60.5 kg is 20+60+56=136.
Derived from ZIMSEC Statistics Paper 4, June 2009, Q3
