A population has mean u=21 and standard deviation o =4. Round the answers to two decimal places as needed. Part 1 of 3 (a) Find the z-score for a population value of 1. The z-score for a population value of 1 is -5 Part 2 of 3 (b) Find the z-score for a population value of 28. The z-score for a population value of 28 is 1.75 Part: 2 / 3 Part 3 of 3 (c) What number has a z-score of 1.8? has a z-score of 1.8. X