Exercise 08.08 Algo (Population Mean: Sigma Known) Question 3 of 7 Hint(s) Check My Work (1 remaining) O Wall Street Journal reported on several studies that show massage therapy has a variety of health benefits and it is not too expensive. A sample of 12 typical one-hour massage therapy sessions showed an average charge of $61. The population standard deviation for a one-hour session is o = $5.1. a. What assumptions about the population should we be willing to make if a margin of error is desired? The population is at least approximately normal is required v b. Using 95% confidence, what is the margin of error (to 2 decimals)? 3.01 c. Using 99%% confidence, what is the margin of error (to 2 decimals)? 3.96 Hide Feedback Partially Correct Hint(s) Check My Work (1 remaining)