Use absolute value to express the distance between −13 and 17 on the number line. (5 points) |−13 − 17| = 4

|−13 − 17| = −4

|−13 − 17| = 30

|−13 − 17| = −30

Studies show that 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 $58. the population standard deviation for a one-hour session is =$5.55. a. what assumptions about the population should we be willing to make if a margin of error is desired? (select your the population has uniform distribution/ the population is at least approximately normal is required/ the population has no exponential distribution/ no assumptions should be made) b. using 90% confidence, what is the margin of error (to 2 decimals) c. using 99% confidence, what is the margin of error (to 2 decimals)