To conclude that the differences are due only to the difference in time of quiz seems very dangerous. A type I error would be concluding that the test time averages are different, when they really are not. A type II error would be concluding that the test time averages are the same, when they are really different. Skip for this exam 7. 270.6 round up, so 271 books needed.
Population mean is m , population proportion is p , and the population standard deviation is s .
Sample mean is xbar, sample standard deviation is s, and sample proportion is p.