A random variable X takes values 0,1,2 with probabilities 0.3,0.5,0.2. The expected value E(X) is: MCQ with Answer and Explanation
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Question #1
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If P(A) = 0.6, P(B) = 0.7, and P(A ∪ B) = 0.9, then P(A ∩ B) is:
Correct Answer: Option B
Explanation:
By addition theorem: P(A∪B) = P(A) + P(B) - P(A∩B) → 0.9 = 0.6 + 0.7 - P(A∩B) → P(A∩B) = 1.3 - 0.9 = 0.4.
By addition theorem: P(A∪B) = P(A) + P(B) - P(A∩B) → 0.9 = 0.6 + 0.7 - P(A∩B) → P(A∩B) = 1.3 - 0.9 = 0.4.
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Accountancy and Statistics
Statistics
Question #2
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In a 2×2 attribute table, if (A)=400, (B)=500, N=1000, and observed (AB)=250, the expected (AB) under independence is:
Correct Answer: Option D
Explanation:
Expected (AB) = (A)×(B)/N = 400×500/1000 = 200,000/1000 = 200. Observed 250 > 200 suggests positive association between attributes A and B.
Expected (AB) = (A)×(B)/N = 400×500/1000 = 200,000/1000 = 200. Observed 250 > 200 suggests positive association between attributes A and B.
This question belongs to:
Accountancy and Statistics
Statistics
Question #3
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When designing a questionnaire, multiple-choice questions are preferred over open-ended questions primarily because:
Correct Answer: Option D
Explanation:
MCQs standardise responses, making data compilation, coding, and statistical tabulation much faster and uniform.
MCQs standardise responses, making data compilation, coding, and statistical tabulation much faster and uniform.
This question belongs to:
Accountancy and Statistics
Statistics
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