The following table shows the cumulative frequency distribution of marks of 800 students in an examination:
| Marks | Number of students |
| Below 10 Below 20 Below 30 Below 40 Below 50 Below 60 Below 70 Below 80 Below 90 Below 100 |
10 50 130 270 440 570 670 740 780 800 |
Construct a frequency distribution table for the data above.
Solution. Frequency distribution: It tells how frequencies are distributed over values in a
frequency distribution. However mostly we use frequency distribution to summarize categorical variables.
| Marks | cf | f |
| 0-10 | 10 | 10 |
| 10-20 | 50 | 50-10=40 |
| 20-30 | 130 | 130-50=80 |
| 30-40 | 270 | 270-130=140 |
| 40-50 | 440 | 440-270=170 |
| 50-60 | 570 | 570-440=130 |
| 60-70 | 670 | 670-570=100 |
| 70-80 | 740 | 740-670=70 |
| 80-90 | 780 | 780-740=40 |
| 90-100 | 800 | 800-780=20 |