Statistics
Exercise 12.1
1. A survey conducted by an organisation for the cause of illness and death among the women between the ages 15 – 44 (in years) worldwide, found the following figures (in %):
| S. No. | Causes | Female fatality rate (%) |
1.
2.
3.
4.
5.
6. | Reproductive health conditions
Neuropsychiatric conditions
Injuries
Cardiovascular conditions
Respiratory conditions
Other causes | 31.8
25.4
12.4
4.3
4.1
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.
2. 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 | Number of girls per thousand boys |
Scheduled Caste (SC)
Scheduled Tribe (ST)
Non SC/ST
Backward districts
Non-backward districts
Rural
Urban | 940
970
920
950
920
930
910 |
(i) Represent the information above by a bar graph.
(ii) In the classroom discuss what conclusions can be arrived at from the graph.
3. 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 |
(i) Draw a bar graph to represent the polling results.
(ii) Which political party won the maximum number of seats?
4. The length 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 – 126 127 – 135 136 – 144 145 – 153 154 – 162 163 – 171 172 – 180 | 3 5 9 12 5 4 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. The following table gives the life times of 400 neon lamps:
| Life time (in hours) | Number of lamps |
300 – 400 400 – 500 500 – 600 600 – 700 700 – 800 800 – 900 900 – 1000 | 14 56 60 86 74 62 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?
6. 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 10 – 20 20 – 30 30 – 40 40 – 50 | 3 9 17 12 9 | 0 – 10 10 – 20 20 – 30 30 – 40 40 – 50 | 5 19 15 10 1 |
Represent the marks of the students of both the sections on the same graph by two frequency polygons. From the two polygons compare the performance of the two sections.
7. 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 7 – 12 13 – 18 19 – 24 25 – 30 31 – 36 37 – 42 43 – 48 49 – 54 55 – 60 | 2 1 8 9 4 5 6 10 6 2 | 5 6 2 10 5 6 3 4 8 10 |
Represent the data of both the teams on the same graph by frequency polygons. [Hint : First make the class intervals continuous.]
8. 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 2 – 3 3 – 5 5 – 7 7 – 10 10 – 15 15 – 17 | 5 3 6 12 9 10 4 |
Draw a histogram to represent the data above.
9. 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 4 – 6 6 – 8 8 – 12 12 – 20 | 6 30 44 16 4 |
(i) Draw a histogram to depict the given information.
(ii) Write the class interval in which the maximum number of surnames lie.