1. Acid rain has caused many lakes to become more acidic. A lake is considered nonacidic if the PH level is greater than 6. The PH level for 15 lakes was:
7.2, 7.3, 6.1, 6.9, 6.6, 7.3, 6.3, 5.5, 6.3, 6.5, 5.7, 6.9, 6.7, 7.9, and 5.8
At "alpha" = 0.05, is there enough evidence to conclude that, on average, these lakes are nonacidic?
2. A used car salesman claims that the average price of a 2009 Honda Accord LX is $20,500. You, of course, distrust him (you feel that it is much lower) and find that a random sample of 14 similar cars has a mean of price of $19,850 with a standard deviation of $1084. Is there enough evidence to reject the salesman's claim at "alpha" = 0.05?
3. Some big shot Institute claims that 25% of college graduates believe that a college degree is not worth the cost. To test this hypothesis you ask a random sample of 200 graduates and 21% agree with that a degree is not worth the cost. At "alpha" = 0.10, is there enough evidence to reject the claim?
4. A 2009 national poll of 1053 U.S. adults found that 548 favored the Governments plan for a stimulus package of a minimum of 800 billion dollars Using "alpha" = 0.05, do the data provide evidence to conclude that a majority (more than 50%) of adults favored passage?