58. A triathlon consisting of swimming, cycling, and running is one of the more strenuous amateur sporting events. The article Cardiovascular and Thermal Response of Triathlon Performance (Med. Sci.

Sports Exercise, 1988: 385—389) reports on a research study involving nine male triathletes. Maximum heart rate (beats/min) was recorded during performance of each of the three events. For swimming, the sample mean and sample standard deviation were 188.0 and 7.2, respectively. Assuming that the heart rate distribution is (approximately) normal, construct a 98% CI for true mean heart rate of triathletes while swimming.