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 mound-shaped distribution, what can we say about the proportion of ratios that fall between:
a. 11.5 and 15.5?
b. 9.5 and 17.5?
c. 7.5 and 19.5?

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The Answer of 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 mound-shaped distribution, what can we say about the proportion of ratios that fall between:
a. 11.5 and 15.5?
b. 9.5 and 17.5?
c. 7.5 and 19.5?

The Price-Earnings Ratios of a Sample of Stocks Have a Mean