The times of the runners in a marathon are normally distributed, with a mean of 3 hours and 50 minutes and a standard deviation of 30 minutes. What is the probability that a randomly selected runner has a time less than or equal to 3 hours and 20 minutes? Use the portion of the standard normal table below to help answer the question. Z Probability 0. 00 0. 5000 0. 50 0. 6915 1. 00 0. 8413 2. 00 0. 9772 3. 00 0. 9987 16% 32% 34% 84%.