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Find the Mean, Variance and Standard Deviation Using Short-cut Method Height in Cms and No. of Children - CBSE (Arts) Class 11 - Mathematics

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Question

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

Class Interval Frequency fi Mid-point xi `y_i = (X_i - 92.5)/5` yi2 fiyi fiyi2

70-75

3

72.5

–4

16

–12

48

75-80

4

77.5

–3

9

–12

36

80-85

7

82.5

–2

4

–14

28

85-90

7

87.5

–1

1

–7

7

90-95

15

92.5

0

0

0

0

95-100

9

97.5

1

1

9

9

100-105

6

102.5

2

4

12

24

105-110

6

107.5

3

9

18

54

110-115

3

112.5

4

16

12

48

 

60

     

6

254

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Solution Find the Mean, Variance and Standard Deviation Using Short-cut Method Height in Cms and No. of Children Concept: Variance and Standard Deviation - Shortcut Method to Find Variance and Standard Deviation.
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