The blood groups of $30$ students of Class $VIII$ are recorded as follows:
$A, B, O, O, AB, O, A, O, B, A, O, B, A, O, O,$
$A, AB, O, A, A, O, O, AB, B, A, O, B, A, B, O.$
Represent this data in the form of a frequency distribution table. Which is the most common,and which is the rarest,blood group among these students?

In a city,the weekly observations made in a study on the cost of living index are given in the following table:

Cost of living index	Number of weeks
$140-150$	$5$
$150-160$	$10$
$160-170$	$20$
$170-180$	$9$
$180-190$	$6$
$190-200$	$2$
Total	$52$

Draw a frequency polygon for the data above (without constructing a histogram).

The lengths of $40$ leaves of a plant are measured correct to one millimetre,and the obtained data is represented in the following table:

Length (in $mm$)	Number of leaves
$118-126$	$3$
$127-135$	$5$
$136-144$	$9$
$145-153$	$12$
$154-162$	$5$
$163-171$	$4$
$172-180$	$2$

$(i)$ Draw a histogram to represent the given data. [Hint: First make the class intervals continuous]
$(ii)$ Is there any other suitable graphical representation for the same data?
$(iii)$ Is it correct to conclude that the maximum number of leaves are $153 \, mm$ long? Why?

$5$ 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.

$A$ survey conducted by an organisation for the cause of illness and death among women between the ages $15-44$ (in years) worldwide,found the following figures (in $\%$):

$S$.No	Causes	Female fatality rate $(\%)$
$1.$	Reproductive health conditions	$31.8$
$2.$	Neuropsychiatric conditions	$25.4$
$3.$	Injuries	$12.4$
$4.$	Cardiovascular conditions	$4.3$
$5.$	Respiratory conditions	$4.1$
$6.$	Other causes	$22.0$

$(i)$ Represent the information given above graphically.
$(ii)$ Which condition is the major cause of women's ill health and death worldwide?
$(iii)$ Try to find out,with the help of your teacher,any two factors which play a major role in the cause in $(ii)$ above being the major cause.

The runs scored by two teams $A$ and $B$ on the first $60$ balls in a cricket match are given below:

Number of balls	Teams $A$	Teams $B$
$1-6$	$2$	$5$
$7-12$	$1$	$6$
$13-18$	$8$	$2$
$19-24$	$9$	$10$
$25-30$	$4$	$5$
$31-36$	$5$	$6$
$37-42$	$6$	$3$
$43-48$	$10$	$4$
$49-54$	$6$	$8$
$55-60$	$2$	$10$

Represent the data of both the teams on the same graph by frequency polygons.
[Hint : First make the class intervals continuous.]