$A$ study was conducted to find out the concentration of sulphur dioxide in the air in parts per million $(ppm)$ of a certain city. The data obtained for $30$ days is as follows:
$\begin{array}{llllll}0.03 & 0.08 & 0.08 & 0.09 & 0.04 & 0.17 \\ 0.16 & 0.05 & 0.02 & 0.06 & 0.18 & 0.20 \\ 0.11 & 0.08 & 0.12 & 0.13 & 0.22 & 0.07 \\ 0.08 & 0.01 & 0.10 & 0.06 & 0.09 & 0.18 \\ 0.11 & 0.07 & 0.05 & 0.07 & 0.01 & 0.04\end{array}$
$(i)$ Make a grouped frequency distribution table for this data with class intervals as $0.00 - 0.04, 0.04 - 0.08$,and so on.
$(ii)$ For how many days was the concentration of sulphur dioxide more than $0.11$ parts per million?

$100$ surnames were randomly picked up from a local telephone directory and a frequency distribution of the number of letters in the English alphabet in the surnames was found as follows:

Number of letters	Number of surnames
$1-4$	$6$
$4-6$	$30$
$6-8$	$44$
$8-12$	$16$
$12-20$	$4$

$(i)$ Draw a histogram to depict the given information.
$(ii)$ Write the class interval in which the maximum number of surnames lie.

Consider the marks obtained by $10$ students in a mathematics test as given below:
$55, 36, 95, 73, 60, 42, 25, 78, 75, 62$

In a mathematics test given to $15$ students,the following marks (out of $100$) are recorded:
$41, 39, 48, 52, 46, 62, 54, 40, 96, 52, 98, 40, 42, 52, 60$
Find the mean,median,and mode of this data.

Van Mahotsava was celebrated in $100$ schools,where $100$ plants were planted in each school. After one month,the number of plants that survived were recorded as follows:
$\begin{array}{llllllllll}95 & 67 & 28 & 32 & 65 & 65 & 69 & 33 & 98 & 96 \\ 76 & 42 & 32 & 38 & 42 & 40 & 40 & 69 & 95 & 92 \\ 75 & 83 & 76 & 83 & 85 & 62 & 37 & 65 & 63 & 42 \\ 89 & 65 & 73 & 81 & 49 & 52 & 64 & 76 & 83 & 92 \\ 93 & 68 & 52 & 79 & 81 & 83 & 59 & 82 & 75 & 82 \\ 86 & 90 & 44 & 62 & 31 & 36 & 38 & 42 & 39 & 83 \\ 87 & 56 & 58 & 23 & 35 & 76 & 83 & 85 & 30 & 68 \\ 69 & 83 & 86 & 43 & 45 & 39 & 83 & 75 & 66 & 83 \\ 92 & 75 & 89 & 66 & 91 & 27 & 88 & 89 & 93 & 42 \\ 53 & 69 & 90 & 55 & 66 & 49 & 52 & 83 & 34 & 36\end{array}$

$A$ teacher wanted to analyze the performance of two sections of students in a mathematics test of $100$ marks. Looking at their performances,she found that a few students got under $20$ marks and a few got $70$ marks or above. So she decided to group them into intervals of varying sizes as follows: $0-20, 20-30, ..., 60-70, 70-100$. Then she formed the following table:

Marks	Number of students
$0-20$	$7$
$20-30$	$10$
$30-40$	$10$
$40-50$	$20$
$50-60$	$20$
$60-70$	$15$
$70-100$	$8$
Total	$90$

$A$ histogram for this table was prepared by a student as shown in Fig. Carefully examine this graphical representation. Do you think that it correctly represents the data?