If X is normally distributed with mean 12 and standard deviation 4, then standard normal variable Z corresponding to X = 18 is:
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → 1.5
$Z = \frac{X - \mu}{\sigma}$
$Z = \frac{18 - 12}{4} = \frac{6}{4} = 1.5$
$Z = 1.5$