$A$ random survey of the number of children of various age groups playing in a park was found as follows:

Age (in years)	Number of children
$1-2$	$5$
$2-3$	$3$
$3-5$	$6$
$5-7$	$12$
$7-10$	$9$
$10-15$	$10$
$15-17$	$4$

Draw a histogram to represent the data above.

The heights (in $cm$) of $9$ students of a class are as follows:
$155, 160, 145, 149, 150, 147, 152, 144, 148$
Find the median of this data. (in $\text{ cm}$)

Give one example of a situation in which $(i)$ the mean is an appropriate measure of central tendency.

Consider the marks obtained (out of $100$ marks) by $30$ students of Class $IX$ of a school:
$\begin{array}{*{20}{c}}
{10}&{20}&{36}&{92}&{95}&{40}&{50}&{56}&{60}&{70} \\
{92}&{88}&{80}&{70}&{72}&{70}&{36}&{40}&{36}&{40} \\
{92}&{40}&{50}&{50}&{56}&{60}&{70}&{60}&{60}&{88}
\end{array}$

The heights of $50$ students,measured to the nearest centimetres,have been found to be as follows:
$\begin{array}{llllllllll}161 & 150 & 154 & 165 & 168 & 161 & 154 & 162 & 150 & 151 \\ 162 & 164 & 171 & 165 & 158 & 154 & 156 & 172 & 160 & 170 \\ 153 & 159 & 161 & 170 & 162 & 165 & 166 & 168 & 165 & 164 \\ 154 & 152 & 153 & 156 & 158 & 162 & 160 & 161 & 173 & 166 \\ 161 & 159 & 162 & 167 & 168 & 159 & 158 & 153 & 154 & 159\end{array}$
$(i)$ Represent the data given above by a grouped frequency distribution table,taking the class intervals as $150-155, 155-160,$ etc.
$(ii)$ What can you conclude about their heights from the table?

The following table gives the distribution of students of two sections according to the marks obtained by them:

Marks (Section $A$)	Frequency (Section $A$)	Marks (Section $B$)	Frequency (Section $B$)
$0-10$	$3$	$0-10$	$5$
$10-20$	$9$	$10-20$	$19$
$20-30$	$17$	$20-30$	$15$
$30-40$	$12$	$30-40$	$10$
$40-50$	$9$	$40-50$	$1$

Represent the marks of the students of both the sections on the same graph by two frequency polygons. From the two polygons,compare the performance of the two sections.