A medical experiment is PLANNED to compare the herb echinacea with a placebo for preventing colds. One response variable will be "volume of nasal secretions" (if you have a cold, you blow your nose a lot). Suppose the average volume of nasal secretions in people without colds is 4. An increase to 8 indicates a cold. (a) Which of the following describes the meaning of the significance level α for a test of the hypotheses: H0: μ = 4 versus Ha: μ > 4 ? α is the probability of selecting a sample whose data leads us to the decision to reject H0 when in reality μ = 4 is true. α is the probability of selecting a sample whose data leads us to the decision to reject H0 when in reality μ = 8 is true. α is the probability of selecting a sample whose data leads us to the decision to fail to reject H0 when in reality μ = 4 is true. α is the probability of selecting a sample whose data leads us to the decision fail to reject H0 when in reality μ = 8 is true. (b) The power of the test in (a) when the true value of the population mean is μ = 8 is The probability of selecting a sample whose data leads us to the decision to reject H0 when μ = 4 is true. The probability of selecting a sample whose data leads us to the decision to reject H0 when μ = 8 is true. a. The probability of selecting a sample whose data leads us to the decision to fail to reject H0 when μ = 4 is true. b. The probability of selecting a sample whose data leads us to the decision to fail to reject H0 when μ = 8 is true.