NCERT Solutions for Class 11 Maths Chapter 15 Statistics Ex 15.2

# NCERT Solutions for Class 11 Maths Chapter 15 Statistics Ex 15.2

## 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, 12

Solution:
Here, xi = 6, 7, 10, 12, 13, 4, 8, 12
Î£ xi = 6 + 7 + 10 + 12 + 13 + 4 + 8 + 12 = 72
n = 8

### Ex 15.2 Class 11 Maths Question 2.

First n natural numbers

Solution:
Here, xi = 1, 2, 3, 4, ………., n

### Ex 15.2 Class 11 Maths Question 3.

First 10 multiples of 3

Solution:
Here, xi = 3, 6, 9, 12, 15, 18, 21, 24, 27, 30
Î£ 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:

NCERT Solutions for Maths Class 9

NCERT Solutions for Maths Class 10

NCERT Solutions for Maths Class 12