Question

The weekly wages of 120 workers in a factory are shown in the following frequency distribution table. Find the mean of the weekly wages.

Weekly wages (Rupees)	0 - 2000	2000 - 4000	4000 - 6000	6000 - 8000
No. of workers	15	35	50	20

Answer 1

Class (Weekly wages in thousand rupees)	Class Mark xi	Frequency (Number of workers) fi	Class mark × Frequency xifi
0 - 2000	1000	15	15000
2000 - 4000	3000	35	105000
4000 - 6000	5000	50	250000
6000 - 8000	7000	20	140000
		`∑f_i = 120`	`∑x_i f_i = 510000`

Mean = `(∑x_i f_i )/(∑f_i )`

          =`510000/120`

          = Rs 4250 

​Hence, the mean of the weekly wages is Rs 4250.