Question

Number of days of medical leave taken by 30 employees in a year is given below.

No. of days	0-10	10-20	20-30	30-40	40-50
No. of employees	5	7	11	4	3

Find the mean number of days of medical leave taken by an employee in a year.

Answer 1

No. of days (Class interval)	Class Marks $\left(x_i\right)$	No. of employees $\left(f_i\right)$	$\left(f_i\right)$$\left(x_i\right)$
0-10	5	5	25
10-20	15	7	105
20-30	25	11	275
30-40	35	4	140
40-50	45	3	135
Total	-	$\sum _{}^{}{f}_i=30$	$\sum _{}^{}{f}_i{x}_i=680$

$\mathrm{Mean}=\overline{x}=\frac{{\displaystyle \sum _{}^{}}{f}_i{x}_i}{{\displaystyle \sum _{}^{}}{f}_i}=\frac{680}{30}=22.67$

Therefore, the mean number of days of medical leave taken by an employee in a year is 22.67 days.