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 6^{th} and 7^{th} 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 5^{th} and 6^{th} observations.
Find the mean deviation about the mean for the data in Exercises 5 and 6.
Ex 13.1 Class 11 Maths Question 5.
x_{i} | 5 | 10 | 15 | 20 | 25 |
f_{i} | 7 | 4 | 6 | 3 | 5 |
Solution:
Ex 13.1 Class 11 Maths Question 6.
x_{i} | 10 | 30 | 50 | 70 | 90 |
f_{i} | 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.
x_{i} | 5 | 7 | 9 | 10 | 12 | 15 |
f_{i} | 8 | 6 | 2 | 2 | 2 | 6 |
Solution:
Ex 13.1 Class 11 Maths Question 8.
x_{i} | 15 | 21 | 27 | 30 | 35 |
f_{i} | 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:
Related Links:
NCERT Solutions for Maths Class 9
NCERT Solutions for Maths Class 10