Table 9.6.2 shows the 2015 performance of stocks recommended by Gene Marcial, whose list was published in Forbes in December 2014. 

a. Compute the average and briefly describe its meaning. 

b. Compute the standard deviation and briefly describe its meaning. 

c. Compute the standard error of the average and briefly describe its meaning. 

d. Find the two-sided 95% confidence interval for the mean performance of stocks recommended by similar informed individuals during this time period, viewing the data set as a random sample from this idealized population. 

e. Find the two-sided 90% confidence interval and compare it to the 95% confidence interval. 

f. Find the one-sided 99% confidence interval statement to the effect that the mean performance was at least as good as some number. 

g. Suppose you decide that, had the data come out with an average performance loss, you would have used a one-sided confidence interval statement that the mean performance was no larger than some number (in place of your answer to part f). In this case, and using the same data table, is your answer to part f a valid confidence interval statement? Why or why not? If not, what should you do instead?

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TABLE 9.6.2 Performance of Recommended Stocks, Rate of Return for 2015 through October Firm Performance (%) Apple 9.64 Bank of America -5.33 CVS Caremark 3.96 Facebook 30.70 Google Class A (now Alphabet) 38.96 Home Depot 19.63 Microsoft 15.63 Pfizer 11.30 TJX Companies 7.66 UnitedHealth Group 17.90 Walt Disney 21.46 Yahoo! -29.48 Apple 9.64 Bank of America -5.33 CVS Caremark 3.96 Source: G. Marcial, A Dozen Stocks to Buy and Hold for 2015, in Forbes December 30, 2014, accessed at http://www.forbes.com/sites/ genemarcial/2014/12/30/a-dozen-stocks-to-buy-and-hold-for-2015/ on November 10, 2015. Stock returns calculated from historical adjusted closing prices accessed at http://finance.yahoo.com on November 10 and 11, 2015.