Consider results of 20 randomly chosen people who have run a marathon. Their times, in minutes, are as follows: 140, 145, 151, 162, 169, 178, 182, 193, 199, 209, 218, 220, 236, 241, 258, 259, 274, 278, 286, 295.Calculate a 90% upper confidence bound in the meantime of the race. Assume distribution to be normal.