Heights of Men in the US Heights of adult males in the US are approximately normally distributed with mean 70 inches $(5$ ft 10 in $)$ and standard deviation 3 inches.
(a) What proportion of US men are between $5 \mathrm{ft}$ 8 in and $6 \mathrm{ft}$ tall $(68$ and 72 inches, respectively)?
(b) If a man is at the 10 th percentile in height, how tall is he?