1. Testing the effect of a diet and exercise regimen on subjects' cholesterol levels, a sports medicine clinic enlists 40 volunteers whose cholesterol levels are mea- sured before and after the 1-month program. The before and after data are listed in data file XR14058. Using the sign test and the 0.025 level of significance, examine the effectiveness of the diet and exercise program. Identify and interpret the p-value for the test.
2. According to R.L. Polk & Company, the median age of automobiles and trucks on the road in the United States is about 9 years. The ages for a random sample of vehicles in the executive parking lot of a metal fabrication company are listed in file XR14059. Using the sign test and the 0.05 level of significance, examine whether the median age for cars driven to work by the com- pany's executives might be less than the median reported by R.L. Polk. Identify and interpret the p-value for the test.
Source: theautochannel.com, July 31, 2009.