Question

Find the mean from the following frequency distribution of marks at a test in class.

Maks ($x$):	$5$	$10$	$15$	$20$	$25$	$30$	$35$	$40$	$45$	$50$
No. of students ($f$)	$15$	$50$	$80$	$76$	$472$	$45$	$39$	$9$	$8$	$6$

Answer 1

Answer:-

Marks (x)	No. of students (f)	fx
$5$	$15$	$75$
$10$	$50$	$500$
$15$	$80$	$1200$
$20$	$76$	$1520$
$25$	$472$	$11800$
$30$	$45$	$1350$
$35$	$39$	$1365$
$40$	$9$	$360$
$45$	$8$	$360$
$50$	$6$	$300$
	$\Sigma f=800$	$\Sigma fx=18830$

Let $\overline{x}$ be the required mean

$\left(\overline{x}\right)=\frac{\Sigma fx}{\Sigma f}=\frac{18830}{800}=23.53$

Hence, Mean $=23.53$