The times for the mile run of a large group of male college students are approximately Normal with mean 7.12 minutes and standard deviation 0.72 minutes. Use the 68-95-99.7 rule to answer the following questions. (Start by making a sketch of the density curve you can use to mark areas on.)

(a) What range of times covers the middle 68% of this distribution? (b) What percent of these men run a mile in more than 8.56 minutes?