NCERT Solutions for Class 11 Maths Chapter 13 Statistics Ex 13.1

# NCERT Solutions for Class 11 Maths Chapter 13 Statistics Ex 13.1

NCERT Solutions for Class 11 Maths Chapter 13 Statistics Ex 13.1 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 13.1.

## NCERT Solutions for Class 11 Maths Chapter 13 Statistics Ex 13.1

Find the mean deviation about the mean for the data in Exercises 1 and 2.

### Ex 13.1 Class 11 Maths Question 1.

4, 7, 8, 9, 10, 12, 13, 17

Solution:
Mean of the given data is calculated as:

### Ex 13.1 Class 11 Maths Question 2.

38, 70, 48, 40, 42, 55, 63, 46, 54, 44

Solution:
Mean of the given data is calculated as:

Find the mean deviation about the median for the data in Exercises 3 and 4.

### Ex 13.1 Class 11 Maths Question 3.

13, 17, 16, 14, 11, 13, 10, 16, 11, 18, 12, 17

Solution:
Arranging the given data in ascending order, we get
10, 11, 11, 12, 13, 13, 14, 16, 16, 17, 17, 18
Here, n = 12 (which is even)
So, the median is the average of 6th and 7th observations.

### Ex 13.1 Class 11 Maths Question 4.

36, 72, 46, 42, 60, 45, 53, 46, 51, 49

Solution:
Arranging the given data in ascending order, we get

36, 42, 45, 46, 46, 49, 51, 53, 60, 72
Here, n = 10 (which is even)
So, the median is the average of 5th and 6th observations.

Find the mean deviation about the mean for the data in Exercises 5 and 6.

### Ex 13.1 Class 11 Maths Question 5.

 xi 5 10 15 20 25 fi 7 4 6 3 5

Solution:

### Ex 13.1 Class 11 Maths Question 6.

 xi 10 30 50 70 90 fi 4 24 28 16 8

Solution:

Find the mean deviation about the median for the data in Exercises 7 and 8.

### Ex 13.1 Class 11 Maths Question 7.

 xi 5 7 9 10 12 15 fi 8 6 2 2 2 6

Solution:

### Ex 13.1 Class 11 Maths Question 8.

 xi 15 21 27 30 35 fi 3 5 6 7 8

Solution:

Find the mean deviation about the mean for the data in Exercises 9 and 10.

### Ex 13.1 Class 11 Maths Question 9.

 Income per day (in Rs.) Number of persons 0 – 100 4 100 – 200 8 200 – 300 9 300 – 400 10 400 – 500 7 500 – 600 5 600 – 700 4 700 – 800 3

Solution:

### Ex 13.1 Class 11 Maths Question 10.

 Heights (in cms) Number of boys 95 – 105 9 105 – 115 13 115 – 125 26 125 – 135 30 135 – 145 12 145 – 155 10

Solution:

### Ex 13.1 Class 11 Maths Question 11.

Find the mean deviation about median for the following data:

 Marks Number of girls 0 – 10 6 10 – 20 8 20 – 30 14 30 – 40 16 40 – 50 4 50 – 60 2

Solution:

### Ex 13.1 Class 11 Maths Question 12.

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

 Age (in years) Number 16 – 20 5 21 – 25 6 26 – 30 12 31 – 35 14 36 – 40 26 41 – 45 12 46 – 50 16 51 – 55 9

[Hint: Convert the given data into continuous frequency distribution by subtracting 0.5 from lower limit and adding 0.5 to the upper limit of each class interval.]

Solution: