Question

The heights of 1,000 college students are normally distributed about a mean value of 170 cm. The standard deviation is 7.2 cm. What is the probability of selecting a students smaller than 158 centimeters.

Answer 1

$\mu=170,\sigma=7.2$

$P(X<158)=P(Z<\frac{158-170}{7.2})$

$=P(Z<-1.67)$

From the normal tables

$=0.0475$