- Statistics
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- Presentation of Data
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- Bar Graph
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- Histogram
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- Measures of Central Tendency
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- How to Solve Mean,Median and Mode problem's
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- Solved exmaples

In this page we have *NCERT book Solutions for Class 9th Maths:statistics* for
EXERCISE 2 . Hope you like them and do not forget to like , social share
and comment at the end of the page.

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 |

(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.

- Bar graph
- Reproductive health conditions

The following data on the number of girls (to the nearest ten) per thousand boys in different sections of Indian society is given below

Section |
No Of girls per thousand boys |

Scheduled Caste(SC) |
940 |

Scheduled Tribe(ST) |
970 |

Non SC/ST |
920 |

Backward districts |
950 |

Non-backward districts |
920 |

Rural |
930 |

Urban |
910 |

ii) In the classroom discuss what conclusions can be arrived at from the graph

It can be observed that maximum number of girls per thousand boys (i.e., 970) is for ST and minimum number of girls per thousand boys (i.e., 910) is for urban.

Also, the number of girls per thousand boys is greater in rural areas than that in urban areas, backward districts than that in non-backward districts, SC and ST than that in non-SC/ST.

Given below are the seats won by different political parties in the polling outcome of a state assembly elections

Political Party |
A |
B |
C |
D |
E |
F |

Seats Won |
75 |
55 |
37 |
29 |
10 |
37 |

ii) Which political party won the maximum number of seats?

We may find that political party 'A' won maximum number of seats.

The length of 40 leaves of a plant are measured correct to one millimeter, and theObtained 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 |

(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?

It can be observed that the length of leaves is represented in a discontinuous class interval having a difference of 1 in between them. Therefore, ½=.5 has to be added to each upper class limit and also have to subtract 0.5 from the lower class limits so as to make the class intervals continuous.

Taking the length of leaves on x-axis and the number of leaves on y-axis, the histogram of this information can be drawn as above.

Here, 1 unit on y-axis represents 2 leaves.

(ii) Other suitable graphical representation of this data is frequency polygon.

(iii) No, as maximum number of leaves (i.e., 12) has their length in between 144.5 mm and 153.5 mm. It is not necessary that all have their lengths as 153 mm

The following table gives the life times of neon lamps:

Life 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 |

(ii) How many lamps have a life time of more than 700 hours?

i)

ii) Number of lamps having lifetime of more than 700 hours =74+62+48=184

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

Section A |
Section B |
||

Marks |
Frequency |
Marks |
Frequency |

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 |

Section A |
Section B |
||||

Marks |
Class Marks |
Frequency |
Marks |
Class Marks |
Frequency |

0-10 |
5 |
3 |
0-10 |
5 |
5 |

10-20 |
15 |
9 |
10-20 |
15 |
19 |

20-30 |
25 |
17 |
20-30 |
25 |
15 |

30-40 |
35 |
12 |
30-40 |
35 |
10 |

40-50 |
45 |
9 |
40-50 |
45 |
1 |

From the graph we can see performance of students of section 'A' is better than the students of section 'B' as for good marks.

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

Number Of balls |
Team A |
Team 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 |

[Hint: First make the class intervals continuous.]

Number Of balls |
Class Marks |
Team A |
Team B |

.5-6.5 |
3.5 |
2 |
5 |

6.5-12.5 |
9.5 |
1 |
6 |

12.5-18.5 |
15.5 |
8 |
2 |

18.5-24.5 |
21.5 |
9 |
10 |

24.5-30.5 |
27.5 |
4 |
5 |

30.5-36.5 |
33.5 |
5 |
6 |

36.5-42.5 |
39.5 |
6 |
3 |

42.5-48.5 |
45.5 |
10 |
4 |

48.5-54.5 |
51.5 |
6 |
8 |

54.5-60.5 |
57.5 |
2 |
10 |

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 |

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 |

- Draw a histogram to depict the given information.

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