Mean of a Grouped Distribution
The mean of a distribution, where x represents the midpoints, f the frequencies, and n = ∑f , is
= 
Example
Listed below is the grouped frequency distribution for the 30 business executives
Find the mean from the grouped frequency distribution.
| Interval | Midpoint, x | Frequency, f | Product, xf |
| 0-4 | 2 | 3 | 6 |
| 5-9 | 7 | 4 | 28 |
| 10-14 | 12 | 6 | 72 |
| 15-19 | 17 | 8 | 136 |
| 20-24 | 22 | 5 | 110 |
| 25-29 | 27 | 3 | 81 |
| 30-34 | 32 | 1 | 32 |
| Total 30 | Total 465 |
= 15.5.