A random variable X has expected value E(X) = 5 and E(X²) = 29. The variance is: MCQ with Answer and Explanation

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A random variable X has expected value E(X) = 5 and E(X²) = 29. The variance is:

A. 5

B. 4

C. 2

D. 24

Answer: Option B

Solution (By JKExamLibrary)

Var(X) = E(X²) - [E(X)]² = 29 - 25 = 4.

This question belongs to: Accountancy and Statistics Statistics

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Practice More Statistics Questions

Question #1 Report Error

Laspeyres price index is 115 and Paasche price index is 110. The Bowley index (arithmetic mean of L and P) is approximately:

A. 110.0

B. 112.0

C. 113.5

D. 112.5

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Correct Answer: Option D

Explanation:
Bowley index = (L+P)/2 = (115+110)/2 = 112.5. (Note: some books call Marshall-Edgeworth-Bowley index, but this is simple arithmetic average).

This question belongs to: Accountancy and Statistics Statistics

Question #2 Report Error

The arithmetic mean of a set of values is 8. If each value is increased by 5, the new mean is:

A. 8

B. 3

C. 40

D. 13

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Correct Answer: Option D

Explanation:
Adding a constant to each observation increases the mean by the same constant.

This question belongs to: Accountancy and Statistics Statistics

Question #3 Report Error

The factor reversal test is satisfied by:

A. Fisher index

B. Paasche index

C. Marshall-Edgeworth index

D. Laspeyres index

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Correct Answer: Option A

Explanation:
Only Fisher's ideal index satisfies both the time reversal and factor reversal tests.

This question belongs to: Accountancy and Statistics Statistics

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