: Over 10000 runners competed in a marathon. The times of the runners follow a normal distribution. Using the information given below, determine the means and the standard deviation for the runners' times.
- only 16% of the runners were able to finish in less than 3 hr 43 min 31 sec.
- 97.5% of the runners needed at least 2 hr 54min 54 sec to complete the marathon.
