Normal Distribution 1 Circumferences of regulation soccer balls have a mean of 69 cm with a standard deviation of 1 50 cm Assume that the circumferences of soccer balls are approximately normally distributed a Roughly what percentage of regulation soccer balls has a circumference that is greater than 69 9 cm Round to the nearest tenth of a percent b If a regulation soccer ball is randomly selected what is the probability that it will have a circumference between 66 9 and 68 9 cm Round to the nearest thousandth c Would it be unusual to randomly select a regulation soccer ball and find that it has a circumference that is greater than 72 3 cm