$5$ people were asked about the time in a week they spend doing social work in their community. They said $10, 7, 13, 20$ and $15$ hours,respectively. Find the mean (or average) time in a week devoted by them for social work.

The following table gives the life times of $400$ neon lamps:

The time (in hours)	Number of lamps
$300-400$	$14$
$400-500$	$56$
$500-600$	$60$
$600-700$	$86$
$700-800$	$74$
$800-900$	$62$
$900-1000$	$48$

$(i)$ Represent the given information with the help of a histogram.
$(ii)$ How many lamps have a life time of more than $700$ hours?

$A$ company manufactures car batteries of a particular type. The lives (in years) of $40$ such batteries were recorded as follows:
$\begin{array}{llllllll}2.6 & 3.0 & 3.7 & 3.2 & 2.2 & 4.1 & 3.5 & 4.5 \\ 3.5 & 2.3 & 3.2 & 3.4 & 3.8 & 3.2 & 4.6 & 3.7 \\ 2.5 & 4.4 & 3.4 & 3.3 & 2.9 & 3.0 & 4.3 & 2.8 \\ 3.5 & 3.2 & 3.9 & 3.2 & 3.2 & 3.1 & 3.7 & 3.4 \\ 4.6 & 3.8 & 3.2 & 2.6 & 3.5 & 4.2 & 2.9 & 3.6\end{array}$
Construct a grouped frequency distribution table for this data,using class intervals of size $0.5$ starting from the interval $2 - 2.5$.

The following observations have been arranged in ascending order. If the median of the data is $63$,find the value of $x.$
$29, 32, 48, 50, x, x+ 2, 72, 78, 84, 95$

Find the mean of the marks obtained by $30$ students of Class $IX$ of a school.
$\begin{array}{llllllllll}10 & 20 & 36 & 92 & 95 & 40 & 50 & 56 & 60 & 70 \\ 92 & 88 & 80 & 70 & 72 & 70 & 36 & 40 & 36 & 40 \\ 92 & 40 & 50 & 50 & 56 & 60 & 70 & 60 & 60 & 88\end{array}$

The relative humidity (in $\%$) of a certain city for a month of $30$ days was as follows:

$98.1$	$98.6$	$99.2$	$90.3$	$86.5$	$95.3$	$92.9$	$96.3$	$94.2$	$95.1$
$89.2$	$92.3$	$97.1$	$93.5$	$92.7$	$95.1$	$97.2$	$93.3$	$95.2$	$97.3$
$96.2$	$92.1$	$84.9$	$90.2$	$95.7$	$98.3$	$97.3$	$96.1$	$92.1$	$89$

$(i)$ Construct a grouped frequency distribution table with classes $84-86, 86-88$,etc.
$(ii)$ Which month or season do you think this data is about?
$(iii)$ What is the range of this data?