# RD Sharma Solution CLass 11 Mathematics Chapter 32 Statistics

## Chapter 32 – Statistics Exercise Ex. 32.1

Question 1

Calculate the mean deviation on the following income
groups of five and seven members from their medians:

 I Income in Rs. II income in Rs. 4000 3800 4200 4000 4400 4200 4600 4400 4800 4600 4800 5800

Solution 1

Note: Answer given in the book is
incorrect.

Question 2

Solution 2

Question 3

Solution 3

Question 4

Solution 4

Question 5

Solution 5

Question 6

Solution 6

Question 7

Solution 7

Question 8

Solution 8

Question 9

Solution 9

Question 10

Solution 10

Question 11

Calculate the mean deviation about the mean of the following data:

(v) 57, 64, 43, 67, 49, 59, 44, 47, 61, 59

Solution 11

Question 12

Solution 12

Question 13

Solution 13

Question 14

Solution 14

Question 15

Solution 15

Question 16

Solution 16

## Chapter 32 – Statistics Exercise Ex. 32.2

Question 1

Find the mean deviation from the mean for the following
data:

 Size: 1 3 5 7 9 11 13 15 Frequency: 3 3 4 14 7 4 3 4

Solution 1

Question 2

Find the mean deviation from the median for the
following data:

 xi 15 21 27 30 fi 3 5 6 7

Solution 2

Note: Answer given in the book is
incorrect.

Question 3

Solution 3

Question 4

Solution 4

Question 5

Solution 5

Question 6

Solution 6

Question 7

Solution 7

Question 8

Solution 8

Question 9

Solution 9

Question 10

Solution 10

Question 11

Solution 11

## Chapter 32 – Statistics Exercise Ex. 32.3

Question 1

Calculate mean deviation about median age for the age
distribution of 100 persons given below:

 Age: 16-20 21-25 26-30 31-35 36-40 41-45 45-50 50-55 Number of persons 5 6 12 14 26 12 16 9

Solution 1

Question 2

Solution 2

Question 3

Solution 3

Question 4

Solution 4

Question 5

Solution 5

Question 6

Solution 6

Question 7

Solution 7

Question 8

Solution 8

Question 9

Solution 9

Question 10

Solution 10

## Chapter 32 – Statistics Exercise Ex. 32.4

Question 1

Show that the two formulae for the standard deviation
of ungrouped data

Solution 1

Question 2

Solution 2

Question 3

Find the mean, variance and standard deviation for the data:

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

Solution 3

Question 4

Solution 4

Question 5

Solution 5

Question 6

Solution 6

Question 7

Solution 7

Question 8
Solution 8
Question 9

Solution 9

Question 10

Solution 10

Question 11

Solution 11

Question 12

Solution 12

Question 13

Solution 13

Question 14

Solution 14

## Chapter 32 – Statistics Exercise Ex. 32.6

Question 1

Calculate mean, variance
and standard deviation of the following frequency distribution:

 Class: 0-10 10-20 20-30 30-40 40-50 50-60 Frequency: 11 29 18 4 5 3

Solution 1

Question 2

Find the mean and variance of frequency distribution
given below:

 xi: 1x <3 3 x<5 5x<7 7x<9 Fi: 6 4 5 1

Solution 2

Note: Answer given in the book is
incorrect.

Question 3

Solution 3

Question 4

Solution 4

Question 5

Solution 5

Question 6

Solution 6

Question 7

Calculate the Mean, median and Standard Deviation of the following distribution:

Solution 7

Question 8

Solution 8

Question 9

Mean and standard deviation of 100 observation were found to be 40 and 10 respectively. If at the time of calculation two observations were wrongly taken as 30 and 70 in place of 3 and 27 respectively, find the correct standard deviation.

Solution 9

Question 10

While calculating the mean and variance of 10 readings , a student wrongly used the reading of 52 for the correct reading 25. He obtained the mean and variance as 45 and 16 respectively. Find the correct mean and the variance.

Solution 10

## Chapter 32 – Statistics Exercise Ex. 32.7

Question 1

Life of bulbs product by two factories A and B are
given below:

 Length of life (in hours):Factory A: 550-650 650-750 750-850 850-950 950-1050 (Number of bulbs)Factor B: 10   22 52 20 16 (Number of bulbs) 8  60 24 15 12

The bulbs of which factory are more consistent from the
point of view of length of life?

Solution 1

Question 2

Following are mark obtained, out of 100, by two
students Ravi and Hashina in 10 tests:

 Ravi: 25 50 45 30 70 42 36 48 35 60 Hashina: 10 70 50 20 95 55 42 60 48 80

Who is more intelligent and who is more consistent?

Solution 2

Question 3

Solution 3

We observe that the average monthly wages in both firms is same i.e. Rs. 2500. Therefore the plant with greater variance will have greater variability. Thus plant B has greater variability in individual wages.

Question 4

Solution 4

Question 5

Solution 5

Question 6

Solution 6

Question 7

Solution 7

Question 8

Solution 8

Question 9

Solution 9

Question 10

Solution 10

Question 11

Solution 11

Question 12

Solution 12

Question 1

Solution 1

Question 2

Solution 2

Question 3

(i)

(ii)

Solution 3

Question 4

(ii)

Solution 4

## Chapter 32 – Statistics Exercise Ex. 32VSAQ

Question 1

Solution 1

Question 2

Solution 2

Question 3

Solution 3

Question 4

Solution 4

Question 5

Solution 5

Question 6

Solution 6

New SD is

Question 7

Solution 7

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