Chapter 15 Statistics Ex – 15.3

Question 1.

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

Solution:

For Group A :

Question 2.

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

Solution:

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:

(i) Which firm A or B pays a larger amount as monthly wages?

(ii) Which firm, AorB, shows greater variability in individual wages?

Solution:

(i) Firm A :
Number of wage earners (n₁) = 586
Mean of monthly wages () = Rs.5253
∴ Total monthly wages = 5253 x 586
= Rs. 3078258
Firm B :
Number of wage earners (n₂) = 648
Mean of monthly wages () = Rs.5253
∴ Total monthly wages = 5253 x 648
= Rs. 3403944
Hence, Firm B pays a larger amount as monthly wages.

(ii) Since both the firms have the same mean of monthly wages, so the firm with a 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:

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:

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: