NCERT Solutions for Class 11 Maths Chapter 15 Statistics Ex 15.1
NCERT Solutions for Class
11 Maths Chapter 15
Statistics Ex 15.1 are the part of NCERT Solutions for Class 11 Maths. Here you
can find the NCERT Solutions for Class 11 Maths Chapter 15 Statistics Ex 15.1.
Find the mean deviation about the mean for the data in Exercises 1 and
2.
Ex 15.1 Class 11 Maths Question 1.
4, 7, 8, 9, 10, 12, 13, 17Solution:
Mean of the given data is calculated as:
Ex 15.1 Class 11 Maths Question 2.
38, 70, 48, 40, 42, 55, 63, 46, 54, 44Solution:
Mean of the
given data is calculated as:
Find the mean deviation about the median for the data in Exercises 3 and
4.
Ex 15.1 Class 11 Maths Question 3.
13, 17, 16, 14, 11, 13, 10, 16, 11, 18, 12, 17Solution:
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 15.1 Class 11 Maths Question 4.
36, 72, 46, 42, 60, 45, 53, 46, 51, 49Solution:
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 15.1 Class 11 Maths Question 5.
x_{i} |
5 |
10 |
15 |
20 |
25 |
f_{i} |
7 |
4 |
6 |
3 |
5 |
Solution:
Ex 15.1 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 15.1 Class 11 Maths Question 7.
x_{i} |
5 |
7 |
9 |
10 |
12 |
15 |
f_{i} |
8 |
6 |
2 |
2 |
2 |
6 |
Solution:
Ex 15.1 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 15.1 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 15.1 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 15.1 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 15.1 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:
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