18. The average annual total return for U.S. Diversified Equity mutual funds from 1999 to 2003 was 4.1% (Business Week, January 26, 2004). A researcher would like to conduct a hy- pothesis test to see whether the returns for mid-cap growth funds over the same period are significantly different from the average for U.S. Diversified Equity funds. a. Formulate the hypotheses that can be used to determine whether the mean annual re- turn for mid-cap growth funds differ from the mean for U.S. Diversified Equity funds. b. A sample of 40 mid-cap growth funds provides a mean return of i = 3.4%. Assume the population standard deviation for mid-cap growth funds is known from previous studies to be o = 2%. Use the sample results to compute the test statistic and p-value for the hypothesis test. c. Ata = .05, what is your conclusion? Chapter 9 Hypothesis Tests 19. The U.S. Department of Labor reported the average hourly earnings for U.S. production workers to be $14.32 per hour in 2001 (The World Almanac, 2003). A sample of 75 pro- duction workers during 2003 showed a sample mean of $14.68 per hour. Assuming the pop- ulation standard deviation o = $1.45, can we conclude that an increase occurred in the mean hourly earnings since 2001? Use a = .05. 20. For the United States, the mean monthly Internet bill is $32.79 per household (CNBC, January 18, 2006). A sample of 50 households in a southern state showed a sample mean of $30.63. Use a population standard deviation of or = $5.60. a. Formulate hypotheses for a test to determine whether the sample data support the con- clusion that the mean monthly Internet bill in the southern state is less than the national mean of $32.79. b. What is the value of the test statistic? c. What is the p-value? d. At a = .01, what is your conclusion