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

Class	Mid value $\left(x\right)$	$f$	$fx$
0-10	5	8	40
10-20	15	5	75
20-30	25	12	300
30-40	35	35	1225
40-50	45	24	1080
50-60	55	16	880
Total		100	3600

Mean$\left(\overline{x}\right)=\frac{\sum fx}{\sum f}$
$=\frac{3600}{100}$
$=36$.