Can you please answer these questions step by step.

15. A normal population has a mean of 60 and a standard deviation of 12. You select a random sample of 9. Compute the probability the sample mean is: a. Greater than 63. b. Less than 56. c. Between 56 and 63. Question 3: 19. Out of a sample of 200 students, 75 indicated that they preferred chocolate ice cream to vanilla ice cream. 3. Estimate the value of the population proportion of those who preferred chocolate ice cream. b. Compute the standard error of the proportion. c. Determine a 90% condence interval for the population proportion of those who preferred chocolate ice cream. d. Interpret your ndings