An investment broker reports that yearly returns on common stocks are normally distributed with a mean of 12.4 percent and a standard deviation of 20.6 percent. (Round all k amounts to three decimal places. A negative sign should be used instead of the parentheses. For Z, use the inverse normal function and round to 3 decimal places.
(a)What percentage of yearly returns are at or below the 7th percentile of the distribution of yearly returns? What percentage are at or above the 7th percentile? Find the 7th percentile of the distribution of yearly returns.
Percentage of yearly returns are at or below the 7th percentile =
Percentage of yearly returns are at or above the 7th percentile =
k =
(b)If the mean changes to 12.7 percent and the standard deviation changes to 18.6 percent, find the first quartile, Q1 , and the third quartile, Q3, of the distribution of yearly returns.
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