A random variable X is normally distributed with a mean of 150 and a variance of 25. Given that
X = 120, its corresponding z-score is 6.0.

Question

Quizplus · Accepted Answer

The z-score formula is (X - mean) / standard deviation. The standard deviation is the square root of the variance, so in this case, the standard deviation is 5.

Using the formula, we get:

(120 - 150) / 5 = -6

Therefore, the corresponding z-score is -6, not 6.

A Random Variable X Is Normally Distributed with a Mean