NCERT Solutions for Class 11 Maths Chapter 13 Statistics Ex 13.2

NCERT Solutions for Class 11 Maths Chapter 13 Statistics Ex 13.2

NCERT Solutions for Class 11 Maths Chapter 13 Statistics Ex 13.2 are the part of NCERT Solutions for Class 11 Maths. Here you can find the NCERT Solutions for Class 11 Maths Chapter 13 Statistics Ex 13.2.


NCERT Solutions for Class 11 Maths Chapter 13 Statistics Ex 13.2


Find the mean and variance for each of the data in Exercises 1 to 5.

Ex 13.2 Class 11 Maths Question 1.

6, 7, 10, 12, 13, 4, 8, 12

Solution:
Here, xi = 6, 7, 10, 12, 13, 4, 8, 12
 Σ xi = 6 + 7 + 10 + 12 + 13 + 4 + 8 + 12 = 72
n = 8


Ex 13.2 Class 11 Maths Question 2.

First n natural numbers

Solution:
Here, xi = 1, 2, 3, 4, ………., n


Ex 13.2 Class 11 Maths Question 3.

First 10 multiples of 3

Solution:
Here, xi = 3, 6, 9, 12, 15, 18, 21, 24, 27, 30
Σ xi = 3 + 6 + 9 + 12 + 15 + 18 + 21 + 24 + 27 + 30 = 165
n = 10


Ex 13.2 Class 11 Maths Question 4.

xi

6

10

14

18

24

28

30

fi

2

4

7

12

8

4

3


Solution:


Ex 13.2 Class 11 Maths Question 5.

xi

92

93

97

98

102

104

109

fi

3

2

3

2

6

3

3


Solution:


Ex 13.2 Class 11 Maths Question 6.

Find the mean and standard deviation using short-cut method

xi

60

61

62

63

64

65

66

67

68

fi

2

1

12

29

25

12

10

4

5


Solution:

Find the mean and variance for the following frequency distributions in Exercises 7 and 8.

Ex 13.2 Class 11 Maths Question 7.

Classes

Frequencies

0 – 30

2

30 – 60

3

60 – 90

5

90 – 120

10

120 – 150

3

150 – 180

5

180 – 210

2


Solution:


Ex 13.2 Class 11 Maths Question 8.

Classes

Frequencies

0 – 10

5

10 – 20

8

20 – 30

15

30 – 40

16

40 – 50

6


Solution:

Ex 13.2 Class 11 Maths Question 9.

Find the mean, variance and standard deviation using short-cut method.

Height in cms

No. of children

70 – 75

3

75 – 80

4

80 – 85

7

85 – 90

7

90 – 95

15

95 – 100

9

100 – 105

6

105 – 110

6

110 – 115

3


Solution:


Ex 13.2 Class 11 Maths Question 10.

The diameters of circles (in mm) drawn in a design are given below:

Diameters

No. of circles

33 – 36

15

37 – 40

17

41 – 44

21

45 – 48

22

49 – 52

25


Calculate the standard deviation and mean diameter of the circles.
[Hint: First make the data continuous by making the classes as 32.5 – 36.5, 36.5 – 40.5, 40.5 – 44.5, 44.5 – 48.5, 48.5 – 52.5 and then proceed.]

Solution:

 


Related Links:

NCERT Solutions for Maths Class 9

NCERT Solutions for Maths Class 10

NCERT Solutions for Maths Class 12

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