The combined mean of two groups with n₁=20, mean₁=50 and n₂=30, mean₂=60 is: MCQ with Answer and Explanation

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The combined mean of two groups with n₁=20, mean₁=50 and n₂=30, mean₂=60 is:

A. 55

B. 57

C. 56

D. 54

Answer: Option C

Solution (By JKSSB Mock Tests)

Combined mean = (20×50 + 30×60) / (20+30) = (1000+1800)/50 = 2800/50 = 56.

This question belongs to: Accountancy and Statistics Statistics

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Practice More Statistics Questions

Question #1

The harmonic mean of 2 and 6 is:

A. 4

B. 2.4

C. 3.6

D. 3

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Correct Answer: Option D

Explanation:
HM = 2 / (1/2 + 1/6) = 2 / (4/6) = 3.

This question belongs to: Accountancy and Statistics Statistics

Question #2

The General Fertility Rate is affected by:

A. Age structure of women of reproductive age

B. Both A and B

C. Total population size

D. Marital status distribution

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Correct Answer: Option B

Explanation:
GFR does not account for age-marital composition; thus it is influenced by the proportion of married women and age distribution within 15-49.

This question belongs to: Accountancy and Statistics Statistics

Question #3

For two events, P(A)=0.4, P(B)=0.3, and P(A∩B)=0.12. Which of the following is true?

A. A and B are independent.

B. A and B are complementary.

C. P(A∪B)=0.52.

D. A and B are mutually exclusive.

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Correct Answer: Option A

Explanation:
0.4×0.3=0.12, so independent. Mutually exclusive would need 0. P(A∪B)=0.4+0.3-0.12=0.58.

This question belongs to: Accountancy and Statistics Statistics

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