uppose that the distribution of heart rates for medium
sized dogs is Normally distributed with a mean of 115 beats per minute and a standard deviation 18 beats per minute. Approximately what percentage of medium-sized dogs have a heart rate below 151 beats per minute?
Use the z score formula: (151-115)/18 = 2.00. Use Table A to find the corresponding proportion, .9772. Since the question is asking for the proportion less than x (151), subtract the proportion from 1.00. The answer should be .0228 = 2.28%.