Fortune compared global equities versus investments in the U.S. market. For the global market, the magazine found an average of 15% return over five years, while for U.S. markets it found an average of 6.2%.4 Suppose that both numbers are based on random samples of 40 investments in each market, with a standard deviation of 3% in the global market and 3.5% in U.S. markets. Conduct a test for equality of average return using α = 0.05, and construct a 95% confidence interval for the difference in average return in the global versus U.S. markets.