| xi | 10 | 30 | 50 | 70 | 90 |
| fi | 4 | 24 | 28 | 16 | 8 |
Answer:
| xi | fi | Cumulative Frequency (xifi) | |di| = |xi – Mean| | fi |di| |
| 10 | 4 | 40 | 40 | 160 |
| 30 | 24 | 720 | 20 | 480 |
| 50 | 28 | 1400 | 0 | 0 |
| 70 | 16 | 1120 | 20 | 320 |
| 90 | 8 | 720 | 40 | 320 |
| Total = 80 | Total = 4000 | Total = 1280 |
= 4000/80
= 50
= 1280/80
= 16
∴ The mean deviation is 16