A normal population has a mean of 21 and a standard deviation of 5. Required: a. Compute the z value associated with 24. Note: Round your answer to 2 decimal places. b. What proportion of the population is between 21 and 24? Note: Round z-score computation to 2 decimal places and your final answer to 4 decimal places. Proportion c. What proportion of the population is less than 18? Note: Round z-score computation to 2 decimal places and your final answer to 4 decimal places. Proportion