The variance of X is 9. What is the variance of Y = 2X - 3?
Answer and explanation
Correct answer: B. 36
- Step 1: Var(aX + b) = a^2 Var(X). Step 2. = 4 x 9 = 36. Answer: 36. Why not the others: 18: The variance is multiplied by the square of 2, not by 2. 15: That doubles and subtracts the constant. 33: A constant does not change the variance, and the factor is squared.
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