The class marks of a frequency distribution are given as follows: $15, 20, 25, \ldots$ The class interval corresponding to the class mark $20$ is:

$A$ football player scored the following number of goals in $10$ matches:
$1, 3, 2, 5, 8, 6, 1, 4, 7, 9$
Since the number of matches is $10$ (an even number),the median is calculated as:
Median $= \frac{5^{\text{th}} \text{ observation} + 6^{\text{th}} \text{ observation}}{2}$
$= \frac{8 + 6}{2} = 7$
Is this the correct answer? If not,why?

$A$ total of $25$ patients admitted to a hospital are tested for blood sugar levels $(mg/dl)$ and the results obtained are as follows:
$\begin{array}{lllll} 87 & 71 & 83 & 67 & 85 \\ 77 & 69 & 76 & 65 & 85 \\ 85 & 54 & 70 & 68 & 80 \\ 73 & 78 & 68 & 85 & 73 \\ 81 & 78 & 81 & 77 & 75 \end{array}$
Find the mean,median,and mode $(mg/dl)$ of the above data.

If the mean of the following data is $20.2,$ find the value of $p:$
$\begin{array}{|c|c|c|c|c|c|} \hline x & 10 & 15 & 20 & 25 & 30 \\ \hline f & 6 & 8 & p & 10 & 6 \\ \hline \end{array}$

The following table gives the distribution of students of sections $A$ and $B$ of a class according to the marks obtained by them.

Marks	Section $A$ Frequency	Section $B$ Frequency
$0-15$	$3$	$3$
$15-30$	$12$	$16$
$30-45$	$28$	$25$
$45-60$	$30$	$27$
$60-75$	$35$	$40$
$75-90$	$13$	$10$

Represent the marks of the students of both the sections on the same graph by two frequency polygons. What do you observe?

In a diagnostic test in mathematics given to students,the following marks (out of $100$) are recorded:
$46, 52, 48, 11, 41, 62, 54, 53, 96, 40, 98, 44$
Which 'average' will be a good representative of the above data and why?