The following distribution gives the number of accidents met by 160 workers in a factory during a month.
No. of accidents (x): | 0 | 1 | 2 | 3 | 4 |
No. of workers (f): | 70 | 52 | 34 | 3 | 1 |
Find the average number of accidents per worker.
Let the assumed mean (A) = 2
No. of accidents (xi) | No. of workers (fi) | ui = xi – A = xi - 2 | fiui |
0 | 70 | -2 | -140 |
1 | 52 | -1 | -52 |
2 | 34 | 0 | 0 |
3 | 3 | 1 | 3 |
4 | 1 | 2 | 2 |
N = 160 | ∑fiui = -187 |
Average number of accidents per day workers = A +
= 2 + =
= 0.83