1. Americans spend nearly $7 billion on Halloween costumes and decorations (The Wall Street Jour- nal, October 27, 2011). The file Halloween.alex contains sample data showing the amount, in dollars, 16 adults spent on a Halloween costume. . What is the edimale of the population mean amount adults spend on a Halloween cordunne? . What is the sample standard deviation? . Provide a 95% confidence interval estimate of the population standard deviation for the amount adults spend on a Halloween costume? 2. At the end of 2008, the variance in the semiannual yields of overseas government bond was 7 =0.70. A group of bond investors met at that time to discuss future trends in overseas bond yields. Some expected the variability in overseas bond yields to increase and others look Un opposite view. The file Yieldsxlax shows the semiannual yields for 12 oveness countries as of March 6, 2009 (Barron's, March 9, 2009). . Compute the men, variance, and standard deviation of the overseas bond yields as of March 6, 2014. . Develop hypotheas to best whether the sample data indicate that the variance in bond yields has changed from that at the end of 21018. . Use ex =0.05 to conduct the hypothesis test formulated before. What is your conclusion? 3. Many smartphones, equxially those of the LTE enabled persuasion, have earned a bad rap for exceptionally poor battery life. Battery life between charges for the Motorola Droid Razr Max average: 20 hours when the primary use is talk time and 7 hours when the primary use is Internet applications (The Wall Street Journal, March 7, 2012). Since the mean hours for talk time usage is greater than the mean hours for Internet usage, the question was raised as to whether the variance in hours of usage is abo greater when the primary use is talk time. The file BalterryTime.xlax contains sample data showing battery hours of use for the two applications