Question 503575
An investment broker reports that the yearly returns on common stocks are approximately normally distributed with a mean return of 12.4 percent and a standard deviation of 20.6 percent.
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On the other hand, the firm reports that the yearly returns on tax free municipal bonds are approximately normally distributed with a mean return of 5.2 percent and a standard deviation of 8.6 percent. 

Find the probability that a randomly selected: 
A) Common stock will give a positive yearly return:::
normalcdf(0,1,0.124,0.206) = 0.7264
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B)Tax free municipal bond will give a positive yearly return.
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C) Common stock will give more than a 10 percent return.
normalcdf(0.1,1,0.124,0.206)= 0.5464
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D) Taxfree municipal bond will give more than a 10 percent return.
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E) Common stock will give a loss of at least 10 percent.
normalcdf(-1,-0.1,0.124,0.206) = 0.1384
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F) Tax free municipal bond will give a loss of at least 10 percent
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Recalling from this problem that yearly returns on common stocks are normally distributed with a mean of 12.4 percent and a standard deviation of 20.6 percent.
A) What percentage of yearly returns are at or below the 10th percentile of the distribution of yearly returns?
normalcdf(-1,0.1,0.124,0.206) = 0.4536
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et. cetera
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Cheers,
Stan H.
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What percentage are at or above the 10th percentile? 
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Find the 10th percentile of the distribution of yearly returns.
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B) Find the first quartile, Q1 
and the third quartile, Q3 
of the distribution of yearly returns.