The following is the distribution of weights (in kg) of 40 persons :
| Weight (in kg) | 40-45 | 45-50 | 50-55 | 55-60 | 60-65 | 65-70 | 70-75 | 70-75 | 
| Number of person | 4 | 4 | 13 | 5 | 6 | 5 | 2 | 1 | 
Construct a cumulative frequency distribution (of the less than type) 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.
| CI. | f | cf | 
| 40-45 | 4 | 4 | 
| 45-50 | 4 | 8 | 
| 50-55 | 13 | 21 | 
| 55-60 | 5 | 26 | 
| 60-65 | 6 | 32 | 
| 65-70 | 5 | 37 | 
| 70-75 | 2 | 39 | 
| 75-80 | 1 | 40 |