NCERT Solutions for Class 11 Maths Chapter 15 Statistics Ex 15.2
NCERT Solutions for Class
11 Maths Chapter 15
Statistics Ex 15.2 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 15.2.
Find the mean and variance for each of the data in Exercises 1 to 5.
Ex 15.2 Class 11 Maths Question 1.
6, 7, 10, 12, 13, 4, 8, 12Solution:
Here, xi = 6, 7, 10, 12, 13, 4, 8, 12
∴ Σ xi = 6 + 7 + 10 + 12 +
13 + 4 + 8 + 12 = 72
n = 8
Ex 15.2 Class 11 Maths Question 2.
First n natural numbersSolution:
Here, xi = 1, 2, 3, 4, ………., n
Ex 15.2 Class 11 Maths Question 3.
First 10 multiples of 3Solution:
Here, xi = 3, 6, 9, 12, 15, 18, 21, 24, 27, 30
Σ xi = 3 + 6 + 9 + 12 + 15 + 18 + 21 + 24 + 27 + 30 = 165
n = 10
Ex 15.2 Class 11 Maths Question 4.
|
xi |
6 |
10 |
14 |
18 |
24 |
28 |
30 |
|
fi |
2 |
4 |
7 |
12 |
8 |
4 |
3 |
Solution:
Ex 15.2 Class 11 Maths Question 5.
|
xi |
92 |
93 |
97 |
98 |
102 |
104 |
109 |
|
fi |
3 |
2 |
3 |
2 |
6 |
3 |
3 |
Solution:
Ex 15.2 Class 11 Maths Question 6.
Find the mean and standard deviation using short-cut method|
xi |
60 |
61 |
62 |
63 |
64 |
65 |
66 |
67 |
68 |
|
fi |
2 |
1 |
12 |
29 |
25 |
12 |
10 |
4 |
5 |
Solution:
Find the mean and variance
for the following frequency distributions in Exercises 7 and 8.
Ex 15.2 Class 11 Maths Question 7.
|
Classes |
Frequencies |
|
0 – 30 |
2 |
|
30 – 60 |
3 |
|
60 – 90 |
5 |
|
90 – 120 |
10 |
|
120 – 150 |
3 |
|
150 – 180 |
5 |
|
180 – 210 |
2 |
Solution:
Ex 15.2 Class 11 Maths Question 8.
|
Classes |
Frequencies |
|
0 – 10 |
5 |
|
10 – 20 |
8 |
|
20 – 30 |
15 |
|
30 – 40 |
16 |
|
40 – 50 |
6 |
Solution:
Ex 15.2 Class 11 Maths Question 9.
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:
Ex 15.2 Class 11 Maths Question 10.
The diameters of circles (in mm) drawn in a design are given below:|
Diameters |
No.
of circles |
|
33 – 36 |
15 |
|
37 – 40 |
17 |
|
41 – 44 |
21 |
|
45 – 48 |
22 |
|
49 – 52 |
25 |
Calculate the standard deviation and mean diameter of the circles.
[Hint: First make the data continuous by making the classes as 32.5 –
36.5, 36.5 – 40.5, 40.5 – 44.5, 44.5 – 48.5, 48.5 – 52.5 and then proceed.]
Solution:
You can also like these:
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