Suppose that on a certain section of I-95 with a posted speed limit of 65 mph, the speeds of all vehicles have a bell-shaped distribution with a mean of 72 mph and a standard deviation of 3 mph.
a. Using the empirical rule, find the percentage of vehicles with the following speeds on this section of I- 95.
i. 63 to 81 mph
ii. 69 to 75 mph