Question: According to J.D. Power & Associates, the mean wait for an airport rental car shuttle bus in 2004 was 19 minutes. In 2005, a random sample of 20 business travelers showed a mean wait of 15 minutes with a standard deviation of 7 minutes. (a) At α = .05, has the mean wait decreased? State the hypotheses and decision rule clearly. (b) Use Excel to find the p-value. Interpret it.