A certain brand of automobile tire has a mean life span of 37,000 miles and a standard deviation of 2,100 miles. K(Assume the life spans of the tires have a bell-shaped distribution.) (a) The life spans of three randomly selected tires are 33,000 miles, 36,000 miles, and 31,000 miles. Find the z-sc that corresponds to each life span. For the life span of 33,000 miles, z-score is (Round to the nearest hundredth as needed.)