
Answer-first summary for fast verification
Answer: I only
## Explanation Let's analyze each statement: **Statement I**: "The sum of two independent random normal variables is also an independent random normal variable." - **TRUE**: This is a fundamental property of normal distributions. If X ~ N(μ₁, σ₁²) and Y ~ N(μ₂, σ₂²) are independent, then X + Y ~ N(μ₁ + μ₂, σ₁² + σ₂²). **Statement II**: "The product of two random normal variables is also a random normal variable." - **FALSE**: The product of two normal variables is NOT normally distributed. In fact, the product follows a more complex distribution (related to the Bessel function). **Statement III**: "The sum of two random lognormal variables is also a random lognormal variable." - **FALSE**: The sum of lognormal variables is NOT lognormal. Lognormal distributions are closed under multiplication, not addition. Therefore, only Statement I is true, which corresponds to option A.
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Which of the following statements are TRUE? I. The sum of two independent random normal variables is also an independent random normal variable. II. The product of two random normal variables is also a random normal variable. III. The sum of two random lognormal variables is also a random lognormal variable.
A
I only
B
II only
C
III only
D
I, II, and III
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