Page No 245:
Question 1:
The blood groups of 30 students of Class VIII are recoded 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?
Page No 245:
Question 2:
The distance (in km) of 40 engineers from their residence to their place of work were found as follows:
5 3 10 20 25 11 13 7 12 31
19 10 12 17 18 11 32 17 16 2
7 9 7 8 3 5 12 15 18 3
12 14 2 9 6 15 15 7 6 12
Construct a grouped frequency distribution table with class size 5 for the data given above taking the first interval as 0 - 5 (5 not included). What main feature do you observe from this tabular representation?
Page No 245:
Question 3:
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
(ii) Which month or season do you think this data is about?
(iii) What is the range of this data?
Page No 245:
Question 4:
The heights of 50 students, measured to the nearest centimeters, have been found to be as follows:
161 150 154 165 168 161 154 162 150 151
162 164 171 165 158 154 156 172 160 170
153 159 161 170 162 165 166 168 165 164
154 152 153 156 158 162 160 161 173 166
161 159 162 167 168 159 158 153 154 159
(i) Represent the data given above by a grouped frequency distribution table, taking the class intervals as 160 - 165, 165 - 170, etc.
(ii) What can you conclude about their heights from the table?
Page No 245:
Question 5:
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:
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
(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?
Page No 246:
Question 6:
Three coins were tossed 30 times simultaneously. Each time the number of heads occurring was noted down as follows:
0 1 2 2 1 2 3 1 3 0
1 3 1 1 2 2 0 1 2 1
3 0 0 1 1 2 3 2 2 0
Prepare a frequency distribution table for the data given above.
Page No 246:
Question 7:
The value of π up to50 decimal places is given below:
3.14159265358979323846264338327950288419716939937510
(i) Make a frequency distribution of the digits from 0 to 9 after the decimal point.
(ii) What are the most and the least frequently occurring digits?
Page No 246:
Question 8:
Thirty children were asked about the number of hours they watched TV programmes in the previous week. The results were found as follows:
1 6 2 3 5 12 5 8 4 8
10 3 4 12 2 8 15 1 17 6
3 2 8 5 9 6 8 7 14 12
(i) Make a grouped frequency distribution table for this data, taking class width 5 and one of the class intervals as 5 - 10.
(ii) How many children watched television for 15 or more hours a week?
Page No 246:
Question 9:
A company manufactures car batteries of a particular type. The lives (in years) of 40 such batteries were recorded as follows:
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
Construct a grouped frequency distribution table for this data, using class intervals of size 0.5 starting from the intervals 2 − 2.5.
Page No 258:
Question 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 |
Page No 259:
Question 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 |
Page No 259:
Question 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 |
Page No 259:
Question 5:
The following table gives the life times of neon lamps:
Length (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 |
Page No 260:
Question 6:
The following table gives the distribution of students of two sections according to the mark 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 |
Page No 260:
Question 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 |
Page No 261:
Question 8:
A random survey of the number of children of various age groups playing in 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 |
Page No 261:
Question 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 |
Page No 269:
Question 1:
The following number of goals was scored by a team in a series of 10 matches:
2, 3, 4, 5, 0, 1, 3, 3, 4, 3
Find the mean, median and mode of these scores.
Page No 269:
Question 2:
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.
Page No 269:
Question 5:
Find the mean salary of 60 workers of a factory from the following table:
Salary (in Rs) | Number of workers |
3000 | 16 |
4000 | 12 |
5000 | 10 |
6000 | 8 |
7000 | 6 |
8000 | 4 |
9000 | 3 |
1000 | 1 |
Total | 60 |
