Question

Calculate the mean of the following distribution :

Class Interval	0-10	10-20	20-30	30-40	40-50	50-60
Frequency	8	5	12	35	24	16

Answer 1

Consider the following distribution:

Class Interval	Frequency (f)	Classmark (x)	fx
0 – 10	8	5	40
10 – 20	5	15	75
20 – 30	12	25	300
30 – 40	35	35	1225
40 – 50	24	45	1080
50 – 60	16	55	880
Total	`n = sum f = 100`		`sum fx = 3600`

Mean = `(sum fx)/n = 3600/100 = 36`