Question

A survey of 1000 men ages 20 to 30 found that their heights were normally distributed, with a mean of 65 inches and a standard deviation of 2.5 inches. How many men have a height that is between 60 inches and 70 inches?

Answer 1

$$P(60<X<70)=P(Z<\dfrac{70-65}{2.5})$$

$$-P(Z\le\dfrac{60-65}{2.5})=P(Z<2)-P(Z\le-2)$$

$$\approx0.97725-0.02275\approx0.9545$$

$$0.9545(1000)=955$$

955 men.