A large group of male runners walk on treadmill for 6 minutes. Their heart rates in beats per minute at the end vary from runner to runner according to the N(104, 12.5) distribution. The heart rate for male non-runners after the same exercise have the N(130, 17) distribution. (a) What percent of runners have heart rates above 135? What percent of non-runners have heart rates above 135?
(b) What is the median heart rate for runners? What is the IQR?
(c) What percent of runners have heart rates between 110 and 125?
(d) A non-runner has a heart rate of 120. What is the standardized score for this non-runner?
What does the z-score tell us?
(e) Lower heart rates are often associated with healthier, more efficient hearts. Below what heart rate would a non-runner need to have to be in the 20th percentile of heart rates among non-runners.