Chapter 15 – Statistics (Ex – 15.3)

Statistics (Ex – 15.3)

Question 1.
From the data given below state which group is more variable, A or B?

NCERT Solutions for Class 11 Maths Chapter 15 Statistics Ex 15.3 1

Solution:
For Group A :

NCERT Solutions for Class 11 Maths Chapter 15 Statistics Ex 15.3 2
NCERT Solutions for Class 11 Maths Chapter 15 Statistics Ex 15.3 3
NCERT Solutions for Class 11 Maths Chapter 15 Statistics Ex 15.3 4

Question 2.
From the prices of shares X and Y below, find out which is more stable in value:

NCERT Solutions for Class 11 Maths Chapter 15 Statistics Ex 15.3 5

Solution:

NCERT Solutions for Class 11 Maths Chapter 15 Statistics Ex 15.3 6
NCERT Solutions for Class 11 Maths Chapter 15 Statistics Ex 15.3 7

Question 3.
An analysis of monthly wages paid to workers in two firms A and B, belonging to the same industry, gives the following results:

NCERT Solutions for Class 11 Maths Chapter 15 Statistics Ex 15.3 8

(i) Which firm A or B pays larger amount as monthly wages?
(ii) Which firm, AorB, shows greater variability in individual wages?

Solution:

(ii) Since both the firms have same mean of monthly wages, so the firm with greater variance will have more variability in individual wages. Thus firm B will have more variability in individual wages.

Question 4.
The following is the record of goals scored by team A in a football session:

NCERT Solutions for Class 11 Maths Chapter 15 Statistics Ex 15.3 9

For the team B, mean number of goals scored per match was 2 with a standard deviation 1.25 goals. Find which team may be considered more consistent?

Solution:
For team A:

NCERT Solutions for Class 11 Maths Chapter 15 Statistics Ex 15.3 10

Question 5.
The sum and sum of squares corresponding to length x (in cm) and weight y (in gm) of 50 plant products are given below:

NCERT Solutions for Class 11 Maths Chapter 15 Statistics Ex 15.3 11

Which is more varying, the length or weight?

Solution:

NCERT Solutions for Class 11 Maths Chapter 15 Statistics Ex 15.3 12
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