Question

The random variable X is best described by a normal distribution with mean of 30 and standard deviation of 6. Find the z-score that corresponds to th following X values. a. X = 21 b. X = 26 c. X = 35 d. X = 42 e. X = 50

Answer 1

$Z=\frac{x-\mu}{\sigma}$

$\mu=30$

$\sigma=6$

$Z(21)=\frac{21-30}{6}=-1.5$

$Z(26)=\frac{26-30}{6}=-0.67$

$Z(35)=\frac{35-30}{6}=0.83$

$Z(42)=\frac{42-30}{6}=2$

$Z(50)=\frac{50-30}{6}=3.33$