According to the test's publishers (www.act.org), scores on the ACT college entrance examination for students graduating in 2001 were normally distributed, with mu=21 and sigma=5 (scores can range from 1-36). What is the probability of having a score greater than20? What is the probability of having a score less than 17? What is the probability of having a score less than 23? What is the probability of having a score between 18 and 25?.