The price-earnings ratios of a sample of stocks have a mean value of 13.5 and a standard deviation of 2. if the ratios have a bell-shaped distribution, what can we say about the poportion of ratios that fall between 9.5 and 17.5?
A) approx 68%
B) approx 95%
C) approx 99.7 %
D approx 75%
E) appox 89%