Suppose that the lifetimes of tires of a certain brand are normally distributed with a mean of 74.500 miles and a standard deviation of o miles. These tires come with a 60,000-mile warranty. The manufacturer of the tires can adjust o during the production process, but the adjustment of o is quite costly. The manufacturer wants to set o once and for all so that only 5% of the tires will fail before warranty expires. Find the standard deviation to be set