Question:
The following distribution gives the number of accidents met by 160 workers in a factory during a month.
Find the average number of accidents per worker.
Solution:
Let the assume mean be $A=2$.
We know that mean, $\bar{X}=A+\frac{1}{N} \sum_{i=1}^{n} f_{i} d_{i}$
Now, we have $N=\sum f_{i}=160, \sum f_{i} d_{i}=-187$ and $A=2$.
Putting the values in the above formula, we get
$\bar{X}=A+\frac{1}{N} \sum_{i=1}^{n} f_{i} d_{i}$
$=2+\frac{1}{160} \times(-187)$
$=2-\frac{187}{160}$
$=2-1.168$
$=0.83$
Hence, the average number of accidents per worker is 0.83.