C.I	0-4	4-8	8-12	12-16	16-20	20-24
frequency	4	7	10	15	11	6

Construct frequency polygon for the following table

$C.I.$	$class-mark$	$Frequency$
Less than $0$	$0$	$0$
$0-4$	$2$	$4$
$4-8$	$6$	$7$
$8-12$	$10$	$10$
$12-16$	$14$	$15$
$16-20$	$18$	$11$
$20-24$	$22$	$6$
More than $24$	$0$	$0$