NCERT Solutions for Class 11 Maths Chapter 15 Statistics Ex 15.3
NCERT Solutions for Class
11 Maths Chapter 15
Statistics Ex 15.3 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 15.3.
Ex 15.3 Class 11 Maths Question 1.
From the data given below state which group is more variable, A or B?
Marks 
Group
A 
Group
B 
10 – 20 
9 
10 
20 – 30 
17 
20 
30 – 40 
32 
30 
40 – 50 
33 
25 
50 – 60 
40 
43 
60 – 70 
10 
15 
70 – 80 
9 
7 
Solution:
For Group A:
Ex 15.3 Class 11 Maths Question 2.
From the prices of shares X and Y below, find out which is more stable in value:
X 
Y 
35 
108 
54 
107 
52 
105 
53 
105 
56 
106 
58 
107 
52 
104 
50 
103 
51 
104 
49 
101 
Solution:
Ex 15.3 Class 11 Maths 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:

Firm
A 
Firm
B 
Number
of wage earners 
586 
648 
Mean
of monthly wages 
Rs 5253 
Rs 5253 
Variance
of the distribution of wages 
100 
121 
(i) Which firm A or B pays larger amount as monthly wages?
(ii) Which firm, A or B, shows greater variability in individual
wages?
Solution:
(i) Firm A:
Number of wage earners (n_{1}) = 586
Mean of monthly wages (x_{1}) = Rs 5253
∴ Total monthly wages = 5253 × 586
= Rs 3078258
Firm B:
Number of wage earners (n_{2}) = 648
Mean of monthly wages (x_{2}) = Rs 5253
∴ Total monthly wages = 5253 × 648
= Rs 3403944
Hence, firm B pays larger amount as monthly wages.
(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.
Ex 15.3 Class 11 Maths Question 4.
The following is the record of goals scored by team A in a football session:
No.
of goals scored 
0 
1 
2 
3 
4 
No.
of matches 
1 
9 
7 
5 
3 
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:
Ex 15.3 Class 11 Maths 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:Which is more varying, the length or weight?
Solution: