A researcher was interested in studying Americans email habits. She suspected that Americans spend less than 7 hours a week answering their email.The General Social Survey in 2002 asked 1,264 respondents, how many hours they spent answering email a week. The sample mean number of hours was 6.02 and the sample standard deviation was 7.80. Find the test statistic. A. 4.47 B. -4.47 C. 5.99 D. -5.99 E. 1.96 Solution The test statistic is Z=(xbar-)/(s/n) =(6.02-7)/(7.8/sqrt(1264)) =-4.47 Answer: B. -4.47.