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

Question

Share Report Error

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

A. 56

B. 55

C. 57

D. 54

Answer: Option A

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

Request complete Subject PDF

Discuss this Question (0)

No comments yet. Be the first to start the discussion!

Practice More Statistics Questions

Question #1

If Yule's coefficient of association (Q) is +1, the attributes are:

A. Independent

B. Completely positively associated

C. Completely dissociated

D. Inconsistent

View Answer & Solution Discuss

Get Complete Subject PDF for Accountancy and Statistics

Correct Answer: Option B

Explanation:
Q = +1 indicates perfect or complete positive association, where the presence of one attribute implies the other.

This question belongs to: Accountancy and Statistics Statistics

Question #2

The addition theorem of probability for two events A and B states that P(A ∪ B) = P(A) + P(B) - P(A ∩ B). This formula accounts for:

A. The conditional probability of A given B

B. The double-counting of outcomes common to both A and B

C. The independence of events

D. The complement of event A

View Answer & Solution Discuss

Get Complete Subject PDF for Accountancy and Statistics

Correct Answer: Option B

Explanation:
Subtracting P(A ∩ B) corrects for the fact that outcomes in the intersection are counted twice when adding P(A) and P(B), ensuring accurate probability calculation for the union.

This question belongs to: Accountancy and Statistics Statistics

Question #3

Perinatal mortality rate includes:

A. Maternal deaths

B. All infant deaths

C. Stillbirths and deaths in the first week of life

D. Deaths under one year

View Answer & Solution Discuss

Get Complete Subject PDF for Accountancy and Statistics

Correct Answer: Option C

Explanation:
Perinatal mortality covers late fetal deaths (stillbirths) and early neonatal deaths (first 7 days).

This question belongs to: Accountancy and Statistics Statistics

Explore All Statistics MCQs