The standard deviation of a normal random variable X is $20.Given that P(X ≤ $10)= 0.1841 we can determine that the mean of the distribution is equal to
A)$13
B)$26
C)$20
D)$28

Question

Quizplus · Accepted Answer

The probability P(X ≤ $10) = 0.1841 corresponds to a z-score of approximately -0.9. Using the z-score formula, z = (X - μ) / σ, where X = 10, σ = 20, and z = -0.9, we can solve for μ: -0.9 = (10 - μ) / 20, which gives μ = 28.

The Standard Deviation of a Normal Random Variable X Is