Question

Frequency distribution of daily commission received by 100 salesman is given below:

Daily commission (in Rs.)	100-120	120-140	140-160	160-180	180-200
No. of salesman	20	45	22	9	4

Find the mean daily commission received by a salesman.

Answer 1

Daily commission (in Rs.) (Class interval)	Class Marks $\left(x_i\right)$	No. of salesman $\left(f_i\right)$	$\left(f_i\right)$$\left(x_i\right)$
100-120	110	20	2200
120-140	130	45	5850
140-160	150	22	3300
160-180	170	9	1530
180-200	190	4	760
Total	-	$\sum _{}^{}{f}_i=100$	$\sum _{}^{}{f}_i{x}_i=13640$

$\mathrm{Mean}=\overline{x}=\frac{{\displaystyle \sum _{}^{}}{f}_i{x}_i}{{\displaystyle \sum _{}^{}}{f}_i}=\frac{13640}{100}=\mathrm{Rs}136.40$

Therefore, mean daily commission received by a salesman is Rs 136.40