Question

Class	0-10	10-20	20-30	30-40	40-50
Frequency	5	15	13	17	10

For the information given above $(\frac{n}{2}-cf)$ will be:

• A. $10$
• B. $20$
• C. $30$
• D. $25$

Answer 1

Answer: (A)

$10$

Class	Frequency	Cumulative - frequency
$0-10$	$5$	$5$
$10-20$	$15$	$20$
$20-30$	$13$	$33$
$30-40$	$17$	$50$
$40-50$	$10$	$60$

Therefore, $n=60$
So, $\frac{n}{2}=\frac{60}{2}=30$
$\therefore$ Median class is $20-30$
$\therefore$ c.f $=$ cumulative frequency preceding to the median class $=20$
$\therefore$ $\frac{n}{2}-cf=30-20=10$