The article mentioned in Problem 7.30 reported that the stock market in Germany had a mean return of 6.9% in 2016. Assume that the returns for stocks on the German stock market were distributed normally, with a mean of 6.9 and a standard deviation of 10. If you select an individual stock from this population, what is the probability that it would have a return

a. Less than 0 (i.e., a loss)?

b. Between -10 and -20?

c. Greater than -5?

If you selected a random sample of four stocks from this population, what is the probability that the sample would have a mean return

d. Less than 0 (a loss)?

e. Between -10 and -20?

f. Greater than -5?

g. Compare your results in parts (d) through (f) to those in (a) through (c).