Breathing rates for humans can be as low as 4 breaths per minute or as high as 70 or 75 for a person doing strenuous exercise. Suppose that the resting breathing rates for college-age students have a distribution that is mound-shaped, with a mean of10and a standard deviation of1.5breathsper minute.

What fraction of all students would have breathing rates in the following intervals?

(a) 8.5to11.5breaths per minute

(b) 7to13breaths per minute

(c) more than14.5or less than5.5breaths per minute