An investment broker reports that yearly returns on common stocks are normally distributed with a mean of 12.41 percent and a standard deviation of 20.64 percent. (round all k amounts to 4 decimal places. negative amounts should be indicated by a minus sign. for z, use the inverse normal function and round to 4 decimal places, except when the percentile for part a is just 5, then you must interpolate.) (a) what percentage of yearly returns are at or below the 10th percentile of the distribution of yearly