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Question

Mathematics Question on Variance and Standard Deviation

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

-Firm AFirm B
No. of wage earners586648
Mean of monthly wagesRs 5253Rs 5253
Variance of the distribution of wages100121

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

(ii) Which firm, A or B, shows greater variability in individual wages?

Answer

(i) Monthly wages of firm A = Rs 5253

Number of wage earners in firm A = 586

∴Total amount paid = Rs 5253 x 586

Monthly wages of firm B = Rs 5253

Number of wage earners in firm B = 648

∴Total amount paid = Rs 5253 x 648

Thus, firm B pays the larger amount as monthly wages as the number of wage earners in firm B are more than the number of wage earners in firm A.

(ii) Variance of the distribution of wages in firm A(σ12)=100A(σ_1^2)=100

∴ Standard deviation of the distribution of wages in firm A ((σ1) =√100=10

Variance of the distribution of wages in firm B(σ22)=121B(σ_2^2)=121

∴ Standard deviation of the distribution of wages in firm B(σ22)=121=11B(σ_2^2)=√121=11

The mean of monthly wages of both the firms is same i.e., 5253.

Therefore, the firm with greater standard deviation will have more variability.

Thus, firm B has greater variability in the individual wages.