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RD Sharma solutions for Mathematics [English] Class 10 chapter 15 - Statistics [Latest edition]

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RD Sharma solutions for Mathematics [English] Class 10 chapter 15 - Statistics - Shaalaa.com
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Solutions for Chapter 15: Statistics

Below listed, you can find solutions for Chapter 15 of CBSE RD Sharma for Mathematics [English] Class 10.


Exercise 15.1Exercise 15.2Exercise 15.3Exercise 15.4Exercise 15.5Exercise 15.6Exercise 15.7Exercise 15.8
Exercise 15.1 [Pages 5 - 6]

RD Sharma solutions for Mathematics [English] Class 10 15 Statistics Exercise 15.1 [Pages 5 - 6]

Exercise 15.1 | Q 1 | Page 5

Calculate the mean for the following distribution:-

x 5 6 7 8 9
f 4 8 14 11 3
Exercise 15.1 | Q 2 | Page 5

Find the mean of the following data:-

x 19 21 23 25 27 29 31
f 13 15 16 18 16 15 13
Exercise 15.1 | Q 3 | Page 5

If the mean of the following data is 20.6. Find the value of p.

x 10 15 P 25 35
f 3 10 25 7 5
Exercise 15.1 | Q 4 | Page 5

If the mean of the following data is 15, find p.

x 5 10 15 20 25
f 6 P 6 10 5
Exercise 15.1 | Q 5 | Page 5

Find the value of p for the following distribution whose mean is 16.6

x 8 12 15 P 20 25 30
f 12 16 20 24 16 8 4
Exercise 15.1 | Q 6 | Page 5

Find the missing value of p for the following distribution whose mean is 12.58

x 5 8 10 12 P 20 25
f 2 5 8 22 7 4 2
Exercise 15.1 | Q 7 | Page 5

Find the missing frequency (p) for the following distribution whose mean is 7.68.

x 3 5 7 9 11 13
f 6 8 15 P 8 4
Exercise 15.1 | Q 8 | Page 5

The following table gives the number of boys of a particular age in a class of 40 students. Calculate the mean age of the students

Age (in years) 15 16 17 18 19 20
No. of students 3 8 10 10 5 4
Exercise 15.1 | Q 9 | Page 6

Candidates of four schools appear in a mathematics test. The data were as follows:-

Schools No. of Candidates Average Score
I 60 75
II 48 80
III NA 55
IV 40 50

If the average score of the candidates of all the four schools is 66, find the number of candidates that appeared from school III.

Exercise 15.1 | Q 10 | Page 6

Five coins were simultaneously tossed 1000 times and at each toss the number of heads were observed. The number of tosses during which 0, 1, 2, 3, 4 and 5 heads were obtained are shown in the table below. Find the mean number of heads per toss.

No. of heads per toss No. of tosses
0 38
1 144
2 342
3 287
4 164
5 25
Total 1000
Exercise 15.1 | Q 11 | Page 6

The arithmetic mean of the following data is 14. Find the value of k

x1 5 10 15 20 25
f1 7 k 8 4 5
Exercise 15.1 | Q 12 | Page 6

The arithmetic mean of the following data is 25, find the value of k.

x1 5 15 25 35 45
f1 3 k 3 6 2
Exercise 15.1 | Q 13 | Page 6

If the mean of the following data is 18.75. Find the value of p.

x 10 15 P 25 30
f 5 10 7 8 2
Exercise 15.1 | Q 14 | Page 6

Find the value of p, if the mean of the following distribution is 20.

x 15 17 19 20+P 23
f 2 3 4 5P 6
Exercise 15.1 | Q 15 | Page 6

Find the missing frequencies in the following frequency distribution if it is known that the mean of the distribution is 50.

x 10 30 50 70 90  
f 17 f1 32 f2 19 Total 120
Exercise 15.2 [Pages 13 - 14]

RD Sharma solutions for Mathematics [English] Class 10 15 Statistics Exercise 15.2 [Pages 13 - 14]

Exercise 15.2 | Q 1 | Page 13

The number of telephone calls received at an exchange per interval for 250 successive one minute intervals are given in the following frequency table: 

No. of calls(x) 0 1 2 3 4 5 6
No. of intervals (f) 15 24 29 46 54 43 39

Compute the mean number of calls per interval.

Exercise 15.2 | Q 2 | Page 13

Five coins were simultaneously tossed 1000 times and at each toss the number of heads were observed. The number of tosses during which 0, 1, 2, 3, 4 and 5 heads were obtained are shown in the table below. Find the mean number of heads per toss.

No. of heads per toss No. of tosses
0 38
1 144
2 342
3 287
4 164
5 25
Total 1000
Exercise 15.2 | Q 3 | Page 13

The following table gives the number of branches and number of plants in the garden of a school.

No. of branches (x) 2 3 4 5 6
No. of plants (f) 49 43 57 38 13

Calculate the average number of branches per plant.

Exercise 15.2 | Q 4 | Page 13

The following table gives the number of children of 150 families in a village. Find the average number of children per family.

No. of children (x) 0 1 2 3 4 5
No. of families (f) 10 21 55 42 15 7
Exercise 15.2 | Q 5 | Page 13

The marks obtained out of 50, by 102 students in a Physics test are given in the frequency table below:

Marks(x) 15 20 22 24 25 30 33 38 45
Frequency (f) 5 8 11 20 23 18 13 3 1

Find the average number of marks.

Exercise 15.2 | Q 6 | Page 13

The number of students absent in a class were recorded every day for 120 days and the information is given in the following frequency table:

No. of students absent (x) 0 1 2 3 4 5 6 7
No. of days (f) 1 4 10 50 34 15 4 2

Find the mean number of students absent per day.

Exercise 15.2 | Q 7 | Page 13

In the first proof reading of a book containing 300 pages the following distribution of misprints was obtained:

No. of misprints per page (x) 0 1 2 3 4 5
No. of pages (f) 154 95 36 9 5 1

Find the average number of misprints per page.

Exercise 15.2 | Q 8 | Page 13

The following distribution gives the number of accidents met by 160 workers in a factory during a month.

No. of accidents(x) 0 1 2 3 4
No. of workers (f) 70 52 34 3 1

Find the average number of accidents per worker.

Exercise 15.2 | Q 9 | Page 14

Find the mean from the following frequency distribution of marks at a test in statistics:

Marks(x) 5 10 15 20 25 30 35 40 45 50
No. of students (f) 15 50 80 76 72 45 39 9 8 6
Exercise 15.3 [Pages 22 - 25]

RD Sharma solutions for Mathematics [English] Class 10 15 Statistics Exercise 15.3 [Pages 22 - 25]

Exercise 15.3 | Q 1 | Page 22

The following table gives the distribution of total household expenditure (in rupees) of manual workers in a city. Find the average expenditure (in rupees) per household.

Expenditure
(in rupees) (x1)
Frequency(f1)
100 - 150 24
150 - 200 40
200 - 250 33
250 - 300 28
300 - 350 30
350 - 400 22
400 - 450 16
450 - 500 7
Exercise 15.3 | Q 2 | Page 22

A survey was conducted by a group of students as a part of their environment awareness programme, in which they collected the following data regarding the number of plants in 20 houses in a locality. Find the mean number of plants per house.

Number of plants 0 - 2 2 - 4 4 - 6 6 - 8 8 - 10 10 - 12 12 - 14
Number of houses 1 2 1 5 6 2 3

Which method did you use for finding the mean, and why?

Exercise 15.3 | Q 3 | Page 22

Consider the following distribution of daily wages of 50 worker of a factory.

Daily wages (in Rs)

100­ − 120

120­ − 140

140 −1 60

160 − 180

180 − 200

Number of workers

12

14

8

6

10

Find the mean daily wages of the workers of the factory by using an appropriate method.

Exercise 15.3 | Q 4 | Page 22

Thirty women were examined in a hospital by a doctor and the number of heartbeats per minute were recorded and summarized as follows. Fine the mean heartbeats per minute for these women, choosing a suitable method.

Number of heartbeats per minute 65 - 68 68 - 71 71 - 74 74 - 77 77 - 80 80 - 83 83 - 86
Number of women 2 4 3 8 7 4 2
Exercise 15.3 | Q 5 | Page 22

Find the mean of each of the following frequency distributions: (5 - 14)

Class interval 0 - 6 6 - 12 12 - 18 18 - 24 24 - 30
Frequency 6 8 10 9 7
Exercise 15.3 | Q 6 | Page 22

Find the mean of each of the following frequency distributions

Class interval 50 - 70 70 - 90 90 - 110 110 - 130 130 - 150 150 - 170
Frequency 18 12 13 27 8 22
Exercise 15.3 | Q 7 | Page 23

Find the mean of each of the following frequency distributions

Class interval 0 - 8 8 - 16 16 - 24 24 - 32 32 - 40
Frequency 6 7 10 8 9
Exercise 15.3 | Q 8 | Page 23

Find the mean of each of the following frequency distributions

Class interval 0 - 6 6 - 12 12 - 18 18 - 24 24 - 30
Frequency 7 5 10 12 6
Exercise 15.3 | Q 9 | Page 23

Find the mean of each of the following frequency distributions

Class interval 0 - 10 10 - 20 20 - 30 30 - 40 40 - 50
Frequency 9 12 15 10 14
Exercise 15.3 | Q 10 | Page 23

Find the mean of each of the following frequency distributions

Class interval 0 - 8 8 - 16 16 - 24 24 - 32 32 - 40
Frequency 5 9 10 8 8
Exercise 15.3 | Q 11 | Page 23

Find the mean of each of the following frequency distributions

Class interval 0 - 8 8 - 16 16 - 24 24 - 32 32 - 40
Frequency 5 6 4 3 2
Exercise 15.3 | Q 12 | Page 23

Find the mean of each of the following frequency distributions

Class interval 10 - 30 30 - 50 50 - 70 70 - 90 90 - 110 110 - 130
Frequency 5 8 12 20 3 2
Exercise 15.3 | Q 13 | Page 23

Find the mean of each of the following frequency distributions

Class interval 25 - 35 35 - 45 45 - 55 55 - 65 65 - 75
Frequency 6 10 8 12 4
Exercise 15.3 | Q 14 | Page 23

Find the mean of each of the following frequency distributions

Classes 25 - 29 30 - 34 35 - 39 40 - 44 45 - 49 50 - 54 55 - 59
Frequency 14 22 16 6 5 3 4
Exercise 15.3 | Q 15 | Page 23

For the following distribution, calculate mean using all suitable methods:

Size of item 1 - 4 4 - 9 9 - 16 16 - 27
Frequency 6 12 26 20
Exercise 15.3 | Q 16 | Page 23

The weekly observations on cost of living index in a certain city for the year 2004 - 2005 are given below. Compute the weekly cost of living index.

Cost of living Index Number of Students
1400 - 1500 5
1500 - 1600 10
1600 - 1700 20
1700 - 1800 9
1800 - 1900 6
1900 - 2000 2
Exercise 15.3 | Q 17 | Page 23

The following table shows the marks scored by 140 students in an examination of a certain paper:

Marks: 0 - 10 10 - 20 20 - 30 30 - 40 40 - 50
Number of students: 20 24 40 36 20

Calculate the average marks by using all the three methods: direct method, assumed mean deviation and shortcut method.

Exercise 15.3 | Q 18 | Page 23

The mean of the following frequency distribution is 62.8 and the sum of all the frequencies is 50. Compute the missing frequency f1 and f2.

Class 0 - 20 20 - 40 40 - 60 60 - 80 80 - 100 100 - 120
Frequency 5 f1 10 f2 7 8
Exercise 15.3 | Q 19 | Page 24

The following distribution shows the daily pocket allowance given to the children of a multistorey building. The average pocket allowance is Rs 18.00. Find out the missing frequency.

Class interval 11 - 13 13 - 15 15 - 17 17 - 19 19 - 21 21 - 23 23 - 25
Frequency 7 6 9 13 - 5 4
Exercise 15.3 | Q 20 | Page 24

If the mean of the following distribution is 27, find the value of p.

Class 0 - 10 10 - 20 20 - 30 30 - 40 40 - 50
Frequency 8 p 12 13 10
Exercise 15.3 | Q 21 | Page 24

In a retail market, fruit vendors were selling mangoes kept in packing boxes. These boxes contained varying number of mangoes. The following was the distribution of mangoes according to the number of boxes.

Number of mangoe 50 − 52 53 − 55 56 − 58 59 − 61 62 − 64
Number of boxes 15 110 135 115 25

Find the mean number of mangoes kept in a packing box. Which method of finding the mean did you choose?

Exercise 15.3 | Q 22 | Page 24

The table below shows the daily expenditure on food of 25 households in a locality.

Daily expenditure (in Rs) 100 − 150 150 − 200 200 − 250 250 − 300 300 − 350
Number of households 4 5 12 2 2

Find the mean daily expenditure on food by a suitable method.

Exercise 15.3 | Q 23 | Page 24

To find out the concentration of SO2 in the air (in parts per million, i.e., ppm), the data was collected for 30 localities in a certain city and is presented below:

concentration of SO2 (in ppm) Frequency
0.00 − 0.04 4
0.04 − 0.08 9
0.08 − 0.12 9
0.12 − 0.16 2
0.16 − 0.20 4
0.20 − 0.24 2

Find the mean concentration of SO2 in the air.

Exercise 15.3 | Q 24 | Page 24

A class teacher has the following absentee record of 40 students of a class for the whole term. Find the mean number of days a student was absent.

Number of days 0 - 6 6 - 10 10 -14 14 -20 20 -28 28 -38 38 -40
Number of students 11 10 7 4 4 3 1
Exercise 15.3 | Q 25 | Page 24

The following table gives the literacy rate (in percentage) of 35 cities. Find the mean literacy rate.

Literacy rate (in %) 45 − 55 55 − 65 65 − 75 75 − 85 85 − 95
Number of cities 3 10 11 8 3
Exercise 15.3 | Q 26 | Page 24

 The following is the cumulative frequency distribution ( of less than type ) of 1000 persons each of age 20 years and above . Determine the mean age .

Age below (in years): 30 40 50 60 70 80
Number of persons : 100 220 350 750 950 1000
Exercise 15.3 | Q 27 | Page 25

If the mean of the following frequency distribution is 18, find the missing frequency.

Class interval 11 – 13 13 – 15 15 – 17 17 – 19 19 – 21 21 – 23 23 – 25
Frequency 3 6 9 13 f 5 4
Exercise 15.3 | Q 28 | Page 25

Find the missing frequencies in the following frequency distribution if it is known that the mean of the distribution is 50.

x 10 30 50 70 90  
f 17 f1 32 f2 19 Total 120
Exercise 15.3 | Q 29 | Page 25

The daily income of a sample of 50 employees are tabulated as follows:

Income (in Rs.): 1-1200 201 -400 401-600 601 - 800
No.of employees : 14 15 14 7

Find the mean daily income of employees.

Exercise 15.4 [Pages 34 - 36]

RD Sharma solutions for Mathematics [English] Class 10 15 Statistics Exercise 15.4 [Pages 34 - 36]

Exercise 15.4 | Q 1 | Page 34

Following are the lives in hours of 15 pieces of the components of aircraft engine. Find the median:

715, 724, 725, 710, 729, 745, 694, 699, 696, 712, 734, 728, 716, 705, 719.

Exercise 15.4 | Q 2 | Page 34

The following is the distribution of height of students of a certain class in a certain city:

Height (in cm): 160 - 162 163 - 165 166 - 168 169 - 171 172 - 174
No. of students: 15 118 142 127 18

Find the median height.

Exercise 15.4 | Q 3 | Page 34

Following is the distribution of I.Q. of loo students. Find the median I.Q.

I.Q.: 55 - 64 65 - 74 75 - 84 85 - 94 95 - 104 105 - 114 115 - 124 125 - 134 135 - 144
No of Students: 1 2 9 22 33 22 8 2 1
Exercise 15.4 | Q 4 | Page 34

Calculate the median from the following data:

Rent (in Rs.): 15 - 25 25 - 35 35 - 45 45 - 55 55 - 65 65 - 75 75 - 85 85 - 95
No. of Houses: 8 10 15 25 40 20 15 7
Exercise 15.4 | Q 5 | Page 34

Calculate the median from the following data:

Marks below: 10 20 30 40 50 60 70 80
No. of students: 15 35 60 84 96 127 198 250
Exercise 15.4 | Q 6 | Page 34

Calculate the missing frequency from the following distribution, it being given that the median of the distribution is 24.

Age in years 0 - 10 10 - 20 20 - 30 30 - 40 40 - 50
No. of persons 5 25 ? 18 7
Exercise 15.4 | Q 7 | Page 34

The following table gives the frequency distribution of married women by age at marriage:

Age (in years) Frequency
15-19 53
20-24 140
25-29 98
30-34 32
35-39 12
40-44 9
45-49 5
50-54 3
55-59 3
60 and above 2

Calculate the median and interpret the results.

Exercise 15.4 | Q 8 | Page 34

Find the following table gives the distribution of the life time of 400 neon lamps:

Life time (in hours) Number of lamps
1500 – 2000 14
2000 – 2500 56
2500 – 3000 60
3000 – 3500 86
3500 – 4000 74
4000 – 4500 62
4500 – 5000 48

Find the median life time of a lamp.

Exercise 15.4 | Q 9 | Page 35

The distribution below gives the weights of 30 students of a class. Find the median weight of the students.

Weight (in kg) 40−45 45−50 50−55 55−60 60−65 65−70 70−75
Number of students 2 3 8 6 6 3 2
Exercise 15.4 | Q 10 | Page 35

Find the missing frequencies and the median for the following distribution if the mean is 1.46.

No. of accidents: 0 1 2 3 4 5 Total
Frequency (No. of days): 46 ? ? 25 10 5 200
Exercise 15.4 | Q 11 | Page 35

An incomplete distribution is given below:

Variable: 10-20 20-30 30-40 40-50 50-60 60-70 70-80
Frequency: 12 30 - 65 - 25 18

You are given that the median value is 46 and the total number of items is 230.

(i) Using the median formula fill up missing frequencies.

(ii) Calculate the AM of the completed distribution.

Exercise 15.4 | Q 12 | Page 35

If the median of the distribution given below is 28.5, find the values of x and y.

Class interval Frequency
0 - 10 5
10 - 20 x
20 - 30 20
30 - 40 15
40 - 50 y
50 - 60 5
Total 60
Exercise 15.4 | Q 13 | Page 35

The median of the following data is 525. Find the missing frequency, if it is given that there are 100 observations in the data:

Class interval Frequency
0 - 100 2
100 - 200 5
200 - 300 f1
300 - 400 12
400 - 500 17
500 - 600 20
600 - 700 f2
700 - 800 9
800 - 900 7
900 - 1000 4
Exercise 15.4 | Q 14 | Page 35

If the median of the following data is 32.5, find the missing frequencies.

Class interval: 0 - 10 10 - 20 20 - 30 30 - 40 40 - 50 50 - 60 60 - 70 Total
Frequency: f1 5 9 12 f2 3 2 40
Exercise 15.4 | Q 15.1 | Page 35

Compute the median for the following data:

Marks No. of students
Less than 10 0
Less than 30 10
Less than 50 25
Less than 70 43
Less than 90 65
Less than 110 87
Less than 130 96
Less than 150 100
Exercise 15.4 | Q 15.2 | Page 35

Compute the median for the following data:

Marks No. of students
More than 150 0
More than 140 12
More than 130 27
More than 120 60
More than 110 105
More than 100 124
More than 90 141
More than 80 150
Exercise 15.4 | Q 16 | Page 36

A survey regarding the height (in cm) of 51 girls of class X of a school was conducted and the following data was obtained:

Height in cm Number of Girls
Less than 140 4
Less than 145 11
Less than 150 29
Less than 155 40
Less than 160 46
Less than 165 51

Find the median height.

Exercise 15.4 | Q 17 | Page 36

A life insurance agent found the following data for distribution of ages of 100 policy holders. Calculate the median age, if policies are given only to persons having age 18 years onwards but less than 60 years.

Age (in years) Number of policy holders
Below 20 2
20 - 25 4
25 - 30 18
30 - 35 21
35 - 40 33
40 - 45 11
45 - 50 3
50 - 55 6
55 - 60 2
Exercise 15.4 | Q 18 | Page 36

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

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

Find the median length of the leaves.

(Hint: The data needs to be converted to continuous classes for finding the median, since the formula assumes continuous classes. The classes then change to 117.5 − 126.5, 126.5 − 135.5… 171.5 − 180.5)

Exercise 15.4 | Q 19 | Page 36

An incomplete distribution is given as follows:

Variable: 0 - 10 10 - 20 20 - 30 30 - 40 40 - 50 50 - 60 60 - 70
Frequency: 10 20 ? 40 ? 25 15

You are given that the median value is 35 and the sum of all the frequencies is 170. Using the median formula, fill up the missing frequencies.

Exercise 15.4 | Q 20 | Page 36

The median of the distribution given below is 14.4 . Find the values of x and y , if the total frequency is 20.

Class interval : 0-6 6-12 12-18 18-24  24-30
Frequency : 4 5 y 1
Exercise 15.4 | Q 21 | Page 36

The median of the following data is 50. Find the values of p and q, if the sum of all the frequencies is 90.

Marks: 20 -30 30-40 40-50 50-60 60-70 70-80 80-90
Frequency: P 15 25 20 q 8 10
Exercise 15.5 [Pages 45 - 48]

RD Sharma solutions for Mathematics [English] Class 10 15 Statistics Exercise 15.5 [Pages 45 - 48]

Exercise 15.5 | Q 1.1 | Page 45

Find the mode of the following data:

3, 5, 7, 4, 5, 3, 5, 6, 8, 9, 5, 3, 5, 3, 6, 9, 7, 4

Exercise 15.5 | Q 1.2 | Page 45

Find the mode of the following data:

3, 3, 7, 4, 5, 3, 5, 6, 8, 9, 5, 3, 5, 3, 6, 9, 7, 4

Exercise 15.5 | Q 1.3 | Page 45

Find the mode of the following data:

15, 8, 26, 25, 24, 15, 18, 20, 24, 15, 19, 15

Exercise 15.5 | Q 2 | Page 45

The shirt sizes worn by a group of 200 persons, who bought the shirt from a store, are as follows:

Shirt size: 37 38 39 40 41 42 43 44
Number of persons: 15 25 39 41 36 17 15 12

Find the model shirt size worn by the group.

Exercise 15.5 | Q 3.1 | Page 45

Find the mode of the following distribution.

Class-interval: 0 - 10 10 - 20 20 - 30 30 - 40 40 - 50 50 - 60 60 - 70 70 - 80
Frequency: 5 8 7 12 28 20 10 10

 

Exercise 15.5 | Q 3.2 | Page 45

Find the mode of the following distribution.

Class-interval: 10 - 15 15 - 20 20 - 25 25 - 30 30 - 35 35 - 40
Frequency: 30 45 75 35 25 15

 

Exercise 15.5 | Q 3.3 | Page 45

Find the mode of the following distribution.

Class-interval: 25 - 30 30 - 35 35 - 40 40 - 45 45 - 50 50 - 55
Frequency: 25 34 50 42 38 14

 

Exercise 15.5 | Q 4 | Page 45

Compare the modal ages of two groups of students appearing for an entrance test:

Age (in years): 16-18 18-20 20-22 22-24 24-26
Group A: 50 78 46 28 23
Group B: 54 89 40 25 17
Exercise 15.5 | Q 5 | Page 46

The marks in science of 80 students of class X are given below: Find the mode of the marks obtained by the students in science.

Marks: 0 - 10 10 - 20 20 - 30 30 - 40 40 - 50 50 - 60 60 - 70 70 - 80 80 - 90 90 - 100
Frequency: 3 5 16 12 13 20 5 4 1 1

 

Exercise 15.5 | Q 6 | Page 46

The following is the distribution of height of students of a certain class in a certain city:

Height (in cm): 160 - 162 163 - 165 166 - 168 169 - 171 172 - 174
No. of students: 15 118 142 127 18

Find the average height of maximum number of students.

Exercise 15.5 | Q 7 | Page 46

The following table shows the ages of the patients admitted in a hospital during a year:

Age (in years) 5 − 15 15 − 25 25 − 35 35 − 45 45 − 55 55 − 65
Number of patients 6 11 21 23 14 5

Find the mode and the mean of the data given above. Compare and interpret the two measures of central tendency.

Exercise 15.5 | Q 8 | Page 46

The following data gives the information on the observed lifetimes (in hours) of 225 electrical components:

Lifetimes (in hours) 0 − 20 20 − 40 40 − 60 60 − 80 80 − 100 100− 120
Frequency 10  35  52  61  38  29 

Determine the modal lifetimes of the components.

Exercise 15.5 | Q 9 | Page 46

The following table gives the daily income of 50 workers of a factory:

Daily income (in Rs) 100 - 120 120 - 140 140 - 160 160 - 180 180 - 200
Number of workers: 12 14 8 6 10

Find the mean, mode and median of the above data.

Exercise 15.5 | Q 10 | Page 46

The following distribution gives the state-wise teacher-student ratio in higher secondary schools of India. Find the mode and mean of this data. Interpret the two measures.

Number of students
per teacher
Number of states/U.T.
15 − 20 3
20 − 25 8
25 − 30 9
30 − 35 10
35 − 40 3
40 − 45 0
45 − 50 0
50 − 55 2
Exercise 15.5 | Q 11 | Page 46

Find the mean, median and mode of the following data: 

Classes: 0 – 50 50 – 100 100 – 150 150 – 200 200 – 250 250 – 300 300 – 350
Frequency: 2 3 5 6 5 3 1
Exercise 15.5 | Q 12 | Page 46

A student noted the number of cars passing through a spot on a road for 100 periods each of 3 minutes and summarised it in the table given below. Find the mode of the data.

Number of cars 0 − 10 10 − 20 20 − 30 30 − 40 40 − 50 50 − 60 60 − 70 70 − 80
Frequency 7 14 13 12 20 11 15 8
Exercise 15.5 | Q 13 | Page 46

The following frequency distribution gives the monthly consumption of electricity of 68 consumers of a locality. Find the median, mean and mode of the data and compare them.

Monthly consumption (in units) Number of consumers
65 - 85 4
85 - 105 5
105 - 125 13
125 - 145 20
145 - 165 14
165 - 185 8
185 - 205 4
Exercise 15.5 | Q 14 | Page 47

100 surnames were randomly picked up from a local telephone directory and the frequency distribution of the number of letters in the English alphabets in the surnames was obtained as follows:

Number of letters Number of surnames
1 - 4 6
4 − 7 30
7 - 10 40
10 - 13 6
13 - 16 4
16 − 19 4

Determine the median number of letters in the surnames. Find the mean number of letters in the surnames? Also, find the modal size of the surnames.

Exercise 15.5 | Q 15 | Page 47

Find the mean, median and mode of the following data:

Classes: 0-20 20-40 40-60 40-60 80-100 100-120 120-140
Frequency: 6 8 10 12 6 5 3

 

Exercise 15.5 | Q 16 | Page 47

The following data gives the distribution of total monthly household expenditure of 200 families of a village. Find the modal monthly expenditure of the families. Also, find the mean monthly expenditure.

Expenditure (in Rs) Number of families
1000 − 1500 24
1500 − 2000 40
2000 − 2500 33
2500 − 3000 28
3000 − 3500 30
3500 − 4000 22
4000 − 4500 16
4500 − 5000 7
Exercise 15.5 | Q 17 | Page 47

The given distribution shows the number of runs scored by some top batsmen of the world in one-day international cricket matches.

Runs scored Number of batsmen
3000 − 4000 4
4000 − 5000 18
5000 − 6000 9
6000 − 7000 7
7000 − 8000 6
8000 − 9000 3
9000 − 10000 1
10000 − 11000 1

Find the mode of the data.

Exercise 15.5 | Q 18 | Page 47

The frequency distribution for agriculture holdings in a village is given below:

Area of land (in hectares)  1 – 3  3 – 5   5 – 7 7 – 9 9 – 11 11 – 13
Number of families  20 45 80 55 40 12

Find the modal agriculture holding per family.

Exercise 15.5 | Q 19 | Page 48

 The monthly income of 100 families are given as below :

   Income in ( in  ₹)   Number of families
  0-5000   8
5000-10000  26
10000-15000 41
15000-20000 16
20000-25000  3
25000-30000 3
30000-35000   2
35000-40000      1

Calculate the modal income.

Exercise 15.6 [Pages 62 - 64]

RD Sharma solutions for Mathematics [English] Class 10 15 Statistics Exercise 15.6 [Pages 62 - 64]

Exercise 15.6 | Q 1 | Page 62

Draw an ogive by less than method for the following data:

No. of rooms: 1 2 3 4 5 6 7 8 9 10
No. of houses: 4 9 22 28 24 12 8 6 5 2

 

Exercise 15.6 | Q 2 | Page 62

The marks scored by 750 students in an examination are given in the form of a frequency distribution table:

Marks No. of students
600 - 640 16
640 - 680 45
680 - 720 156
720 - 760 284
760 - 800 172
800 - 840 59
840 - 880 18
Exercise 15.6 | Q 3 | Page 63

Draw an ogive to represent the following frequency distribution:

Class-interval: 0 - 4 5 - 9 10 - 14 15 - 19 20 - 24
Frequency: 2 6 10 5 3
Exercise 15.6 | Q 4 | Page 63

The monthly profits (in Rs.) of 100 shops are distributed as follows:

Profits per shop: 0 - 50 50 - 100 100 - 150 150 - 200 200 - 250 250 - 300
No. of shops: 12 18 27 20 17 6

Draw the frequency polygon for it.

Exercise 15.6 | Q 5 | Page 63

The following distribution gives the daily income of 50 workers of a factory.

Daily income (in Rs 100 − 120 120 − 140 140 − 160 160 − 180 180 − 200
Number of workers 12 14 8 6 10

Convert the distribution above to a less than type cumulative frequency distribution, and draw its ogive.

Exercise 15.6 | Q 6 | Page 63

The following table gives production yield per hectare of wheat of 100 farms of a village:

Production yield in kg per hectare: 50 - 55 55 - 60 60 - 65 65 - 70 70 - 75 75 - 80
Number of farms: 2 8 12 24 38 16

Draw ‘less than’ ogive and ‘more than’ ogive.

Exercise 15.6 | Q 7 | Page 63

During the medical check-up of 35 students of a class, their weights were recorded as follows:

Weight (in kg Number of students
Less than 38 0
Less than 40 3
Less than 42 5
Less than 44 9
Less than 46 14
Less than 48 28
Less than 50 32
Less than 52 35

Draw a less than type ogive for the given data. Hence obtain the median weight from the graph verify the result by using the formula.

Exercise 15.6 | Q 8 | Page 63

The annual rainfall record of a city for 66 days is given in the following table :

Rainfall (in cm ):   0-10 10-20   20-30   30-40   40-50 50-60
Number of days : 22 10 8 15 5 6

Calculate the median rainfall using ogives of more than type and less than type.

Exercise 15.6 | Q 9 | Page 64

The following table gives the height of trees:
 

Height No. of trees
Less than 7
Less than 14
Less than 21
Less than 28
Less than 35
Less than 42
Less than 49
Less than 56
26
57
92
134
216
287
341
360


Draw 'less than' ogive and 'more than' ogive.

 

Exercise 15.6 | Q 10 | Page 64

The annual profits earned by 30 shops of a shopping complex in a locality give rise to the following distribution:
 

Profit (in lakhs in Rs) Number of shops (frequency)
More than or equal to 5
More than or equal to 10
More than or equal to 15
More than or equal to 20
More than or equal to 25
More than or equal to 30
More than or equal to 35
30
28
16
14
10
7
3


Draw both ogives for the above data and hence obtain the median.

Exercise 15.7 [Pages 65 - 66]

RD Sharma solutions for Mathematics [English] Class 10 15 Statistics Exercise 15.7 [Pages 65 - 66]

Exercise 15.7 | Q 1 | Page 65

Define mean.

Exercise 15.7 | Q 2 | Page 65

What is the algebraic sum of deviation of a frequency distribution about its mean?

Exercise 15.7 | Q 3 | Page 65

Which measure of central tendency is given by the x-coordinate of the point of intersection of the 'more than' ogive and 'less than' ogive?

Exercise 15.7 | Q 4 | Page 65

What is the value of the median of the data using the graph in the following figure of less than ogive and more than ogive?

Exercise 15.7 | Q 5 | Page 65

Write the empirical relation between mean, mode and median.

Exercise 15.7 | Q 6 | Page 65

Which measure of central tendency can be determine graphically?

Exercise 15.7 | Q 7 | Page 65

Write the modal class for the following frequency distribution:

Class-interval: 10−15 15−20 20−25 25−30 30−35 35−40
Frequency: 30 35 75 40 30 15

 

Exercise 15.7 | Q 8 | Page 65

A student draws a cumulative frequency curve for the marks obtained by 40 students of a class as shown below. Find the median marks obtained by the students of the class.

Exercise 15.7 | Q 9 | Page 65

Write the median class for the following frequency distribution:

Class-interval: 0−10 10−20 20−30 30−40 40−50 50−60 60−70 70−80
Frequency: 5 8 7 12 28 20 10 10
Exercise 15.7 | Q 10 | Page 66

In the graphical representation of a frequency distribution, if the distance between mode and mean is ktimes the distance between median and mean, then write the value of k.

Exercise 15.7 | Q 11 | Page 66

Find the class marks of classes 10−25 and 35−55.

Exercise 15.7 | Q 12 | Page 66

Write the median class of the following distribution:

Class-interval: 0−10 10−20 20−30 30−40 40−50 50−60 60−70
Frequency: 4 4 8 10 12 8 4
Exercise 15.8 [Pages 66 - 69]

RD Sharma solutions for Mathematics [English] Class 10 15 Statistics Exercise 15.8 [Pages 66 - 69]

Exercise 15.8 | Q 1 | Page 66

Which of the following is not a measure of central tendency?

  • Mean

  • Median

  •  Mode

  • Standard deviation

Exercise 15.8 | Q 2 | Page 66

The algebraic sum of the deviations of a frequency distribution from its mean is always ______.

  • Always positive

  • Always negative

  • Zero

  • A non-zero number

Exercise 15.8 | Q 3 | Page 66

The arithmetic mean of 1, 2, 3, ... , n is

  • \[\frac{n + 1}{2}\]

  • \[\frac{n - 1}{2}\]

  • \[\frac{n}{2}\]

  • \[\frac{n}{2} + 1\]

Exercise 15.8 | Q 4 | Page 66

For a frequency distribution, mean, median and mode are connected by the relation

  •  Mode = 3 Mean − 2 Median

  • Mode = 2 Median − 3 Mean

  • Mode = 3 Median − 2 Mean

  • Mode = 3 Median + 2 Mean

Exercise 15.8 | Q 5 | Page 66

Which of the following cannot be determined graphically?

  • Mean

  • Median

  • Mode

  • None of these

Exercise 15.8 | Q 6 | Page 66

The median of a given frequency distribution is found graphically with the help of

  •  Histogram

  • Frequency curve

  • Frequency polygon

  • Ogive

Exercise 15.8 | Q 7 | Page 66

The mode of a frequency distribution can be determined graphically from ______.

  • Histogram

  • Frequency polygon

  • Ogive

  • Frequency curve

Exercise 15.8 | Q 8 | Page 66

Mode is

  •  least frequency value

  • middle most value

  • most frequent value

  • None of these

Exercise 15.8 | Q 9 | Page 66

The mean of n observation is `overlineX` . If the first item is increased by 1, second by 2 and so on, then the new mean is

  •  `overlineX+n`

  •  `overlineX+n/2`

  •  `overlineX+(n+1)/2`

  • None of these

Exercise 15.8 | Q 10 | Page 66

One of the methods of determining mode is ______.

  •  Mode = 2 Median - 3 Mean

  •  Mode = 2 Median + 3 Mean

  • Mode = 3 Median - 2 Mean

  • Mode = 3 Median + 2 Mean

Exercise 15.8 | Q 11 | Page 67

If the mean of the following distribution is 2.6, then the value of y is:

Variable (x) 1 2 3 4 5
Frequency 4 5 y 1 2
  • 3

  • 8

  • 13

  • 24

Exercise 15.8 | Q 12 | Page 67

The relationship between mean, median and mode for a moderately skewed distribution is.

  • Mode = 2 Median - 3 Mean

  •  Mode = Median - 2 Mean

  • Mode = 2 Median - Mean

  •  Mode = 3 Median - 2 Mean

Exercise 15.8 | Q 13 | Page 67

The mean of a discrete frequency distribution xi / fi, i = 1, 2, ......, n is given by

  • `overlineX = (sum f_ix_i)/(sumf_i)`

  • \[\frac{1}{n} \sum^n_{i = 1} f_i x_i\]

  • \[\frac{\sum^n_{i = 1} f_i x_i}{\sum^n_{i = 1} x_i}\]

  • \[\frac{\sum^n_{i = 1} f_i x_i}{\sum^n_{1 = 1} i}\]

Exercise 15.8 | Q 14 | Page 67

If the arithmetic mean of x, x + 3, x + 6, x + 9, and x + 12 is 10, the x =

  • 1

  • 2

  • 6

  • 4

Exercise 15.8 | Q 15 | Page 67

If the median of the data: 24, 25, 26, x + 2, x + 3, 30, 31, 34 is 27.5, then x =

  • 27

  • 25

  • 28

  • 30

Exercise 15.8 | Q 16 | Page 67

If the median of the data: 6, 7, x − 2, x, 17, 20, written in ascending order, is 16. Then x=

  • 15

  • 16

  • 17

  • 18

Exercise 15.8 | Q 17 | Page 67

The median of first 10 prime numbers is

  • 11

  • 12

  • 13

  • 14

Exercise 15.8 | Q 18 | Page 67

If the mode of the data: 64, 60, 48, x, 43, 48, 43, 34 is 43, then x + 3 =

  • 44

  • 45

  • 46

  • 48

Exercise 15.8 | Q 19 | Page 67

If the mode of the data: 16, 15, 17, 16, 15, x, 19, 17, 14 is 15, then x =

  • 15

  • 16

  • 17

  • 19

Exercise 15.8 | Q 20 | Page 67

The mean of 1, 3, 4, 5, 7, 4 is m. The numbers 3, 2, 2, 4, 3, 3, p have mean m − 1 and median q. Then, p + q =

  • 4

  • 5

  • 6

  • 7

Exercise 15.8 | Q 21 | Page 67

If the mean of frequency distribution is 8.1 and Σfixi = 132 + 5k, Σfi = 20, then k =?

  • 3

  • 4

  • 5

  • 6

Exercise 15.8 | Q 22 | Page 67

If the mean of 6, 7, x, 8, y, 14 is 9, then ______.

  •  x + y = 21

  • x + y = 19

  • x − y = 19

  • x − y = 21

Exercise 15.8 | Q 23 | Page 67

The mean of n observation is `overlineX`.  If the first observation is increased by 1, the second by 2, the third by 3, and so on, then the new mean is

  • `overlineX`\[ + \left( 2n + 1 \right)\]
  • `overlineX`\[+ \frac{n + 1}{2}\]
  • `overlineX`\[ + \left( n + 1 \right)\]
  • `overlineX`\[ - \frac{n + 1}{2}\]

Exercise 15.8 | Q 24 | Page 67

If the mean of first n natural numbers is \[\frac{5n}{9}\], then n =

  • 5

  • 4

  • 9

  • 10

Exercise 15.8 | Q 25 | Page 68

The arithmetic mean and mode of a data are 24 and 12 respectively, then its median is

  • 25

  • 18

  • 20

  • 22

Exercise 15.8 | Q 26 | Page 68

The mean of first n odd natural number is

  • \[\frac{n + 1}{2}\]

  • \[\frac{n}{2}\]

  • n

  • `n^2`

Exercise 15.8 | Q 27 | Page 68

The mean of first n odd natural numbers is \[\frac{n^2}{81}\],then n =

  • 9

  • 81

  • 27

  • 18

Exercise 15.8 | Q 28 | Page 68

If the difference of Mode and Median of a data is 24, then the difference of median and mean is ______.

  • 12

  • 24

  • 8

  • 36

Exercise 15.8 | Q 29 | Page 68

If the arithmetic mean, 7, 8, x, 11, 14 is x, then x =

  • 9

  • 9.5

  • 10

  • 10.5

Exercise 15.8 | Q 30 | Page 68

If mode of a series exceeds its mean by 12, then mode exceeds the median by

  • 4

  • 8

  • 6

  • 10

Exercise 15.8 | Q 31 | Page 68

If the mean of first n natural number is 15, then n =

  • 15

  • 30

  • 14

  • 29

Exercise 15.8 | Q 32 | Page 68

If the mean of observation \[x_1 , x_2 , . . . . , x_n is x\]  then the mean of x1 + a, x2 + a, ....., xn + a is 

  • a`overlineX`

  • `overlineX -a`

  • `overlineX +a`

  • `overlineX/a`

Exercise 15.8 | Q 33 | Page 68

Mean of a certain number of observation is `overlineX`.  If each observation is divided by m(m ≠ 0) and increased by n, then the mean of new observation is

  • `overlineX/m +n`

  • `overlineX/n+m`

     

  • `overlineX +n/m`

  • `overlineX +m/n`

Exercise 15.8 | Q 34 | Page 68

If \[u_i = \frac{x_i - 25}{10}, \Sigma f_i u_i = 20, \Sigma f_i = 100, \text { then }\]`overlineX`

  • 23

  • 24

  • 27

  • 25

Exercise 15.8 | Q 35 | Page 68

If 35 is removed from the data: 30, 34, 35, 36, 37, 38, 39, 40, then the median increased by

  • 2

  • 1.5

  • 1

  • 0.5

Exercise 15.8 | Q 36 | Page 68

While computing mean of grouped data, we assume that the frequencies are ______.

  • evenly distributed over all the classes

  •  centred at the class marks of the classes

  • centred at the upper limit of the classes

  •  centred at the lower limit of the classes

Exercise 15.8 | Q 37 | Page 68

In the formula  `barx=a+h((sumf_iu_i)/(sumf_i))`, for finding the mean of grouped frequency distribution ui = ______.

  • `(x_i+a)/h`

  • h(xi - a)

  • `(x_i-a)/h`

  • `(a-x_i)/h`

Exercise 15.8 | Q 38 | Page 69

For the following distribution:

Class 0 – 5 5 – 10 10 – 15 15 – 20 20 – 25
Frequency 10 15 12 20 9

The sum of lower limits of the median class and modal class is:

  • 15

  • 25

  • 30

  • 35

Exercise 15.8 | Q 39 | Page 69

For the following distribution:

Marks Number of students
Below 10 3
Below 20 12
Below 30 27
Below 40 57
Below 50 75
Below 60 80

The modal class is ______.

  • 10 − 20

  • 20 − 30

  • 30 − 40

  • 50 − 60

Exercise 15.8 | Q 40 | Page 69

Consider the following frequency distributions

Class 65 - 85 85 - 105 105 - 125 125 - 145 145 - 165 165 - 185 185-205
Frequency 4 5 13 20 14 7 4

The difference of the upper limit of the median class and the lower limit of the modal class is?

  • 0

  • 19

  • 20

  • 38

Exercise 15.8 | Q 41 | Page 69

 In the formula 

`overlineX``\[= a + \frac{\Sigma f_i d_i}{\Sigma f_i}\], for finding the mean of grouped data \[{d_i}^{'^s}\]   are derivations from \[a\] of
  • lower limits of classes

  • upper limits ofclasses   

  •  mid-points of classes    

  •  frequency of the class marks 

Exercise 15.8 | Q 42 | Page 69

The abscissa of the point of intersection of less than type and of the more than types cumulative frequency curves of a grouped data gives its ______.

  • Mean   

  • Median

  • Mode

  • All of the above

Exercise 15.8 | Q 43 | Page 69

Consider the following frequency distribution :

Class: 0-5      6-11   12-17  18-23   24-29
Frequency:   13 10 15 8 11

The upper limit of the median class is 

  • 17

  •   17.5   

  • 18

  • 18.5

Solutions for 15: Statistics

Exercise 15.1Exercise 15.2Exercise 15.3Exercise 15.4Exercise 15.5Exercise 15.6Exercise 15.7Exercise 15.8
RD Sharma solutions for Mathematics [English] Class 10 chapter 15 - Statistics - Shaalaa.com

RD Sharma solutions for Mathematics [English] Class 10 chapter 15 - Statistics

Shaalaa.com has the CBSE Mathematics Mathematics [English] Class 10 CBSE solutions in a manner that help students grasp basic concepts better and faster. The detailed, step-by-step solutions will help you understand the concepts better and clarify any confusion. RD Sharma solutions for Mathematics Mathematics [English] Class 10 CBSE 15 (Statistics) include all questions with answers and detailed explanations. This will clear students' doubts about questions and improve their application skills while preparing for board exams.

Further, we at Shaalaa.com provide such solutions so students can prepare for written exams. RD Sharma textbook solutions can be a core help for self-study and provide excellent self-help guidance for students.

Concepts covered in Mathematics [English] Class 10 chapter 15 Statistics are Ogives (Cumulative Frequency Graphs), Applications of Ogives in Determination of Median, Relation Between Measures of Central Tendency, Introduction to Normal Distribution, Properties of Normal Distribution, Concept of Pie Graph (Or a Circle-graph), Tabulation of Data, Inclusive and Exclusive Type of Tables, Mean of Grouped Data, Median of Grouped Data, Graphical Representation of Data as Histograms, Frequency Polygon, Mode of Grouped Data, Concepts of Statistics, Method of Finding Mean for Grouped Data: Direct Method, Method of Finding Mean for Grouped Data: Deviation Or Assumed Mean Method, Method of Finding Mean for Grouped Data: the Step Deviation Method, Concept of Pictograph, Presentation of Data, Interpretation of Pie Diagram, Drawing a Pie Graph, Mean of Grouped Data, Mode of Grouped Data, Median of Grouped Data, Graphical Representation of Cumulative Frequency Distribution, Ogives (Cumulative Frequency Graphs), Concepts of Statistics, Concepts of Statistics.

Using RD Sharma Mathematics [English] Class 10 solutions Statistics exercise by students is an easy way to prepare for the exams, as they involve solutions arranged chapter-wise and also page-wise. The questions involved in RD Sharma Solutions are essential questions that can be asked in the final exam. Maximum CBSE Mathematics [English] Class 10 students prefer RD Sharma Textbook Solutions to score more in exams.

Get the free view of Chapter 15, Statistics Mathematics [English] Class 10 additional questions for Mathematics Mathematics [English] Class 10 CBSE, and you can use Shaalaa.com to keep it handy for your exam preparation.

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