Industrial emissions of sulfur dioxide set off chemical changes in the atmosphere that result in "acid rain." The acidity of liquids is measured by pH on a scale of 0 to 14. Distilled water has a pH of 7.0, and lower pH values indicate acidity. Normal rain is somewhat acidic, so acid rain is sometimes defined as rainfall with a pH below 5.0. Suppose that pH measurements of rainfall on different days in a Canadian forest follow a Normal distribution with standard deviation = 0.5. A sample of n days finds that the mean pH is xx = 4.8. What are the P-values for tests of sample sizes n = 5, n = 15 and n = 40?

n = 5: n = 15: n = 40: