Question

Find the median :

Weight	No of students
$40-45$	$2$
$45-50$	$3$
$50-55$	$8$
$55-60$	$6$
$60-65$	$6$
$65-70$	$3$
$70-75$	$2$

Answer 1

$Weight$	$No.ofstudents$	$c.f.$
$40-45$	$2$	$2$
$45-50$	$3$	$5$
$50-55$	$8$	$13$
$55-60$	$6$	$19$
$60-65$	$6$	$25$
$65-70$	$3$	$28$
$70-75$	$2$	$30$

$N=30$ and $\frac{N}{2}=\frac{30}{2}=15$

$\therefore$ Median class $=55-60$

$l=55,c.f=13,f=6$ and $h=5$

$Median=l+\frac{\frac{N}{2}-c.f}{f}\times h$

$=55+\frac{15-13}{6}\times 5$

$=55+1.66$

$=56.66$