CHALLENGE YOURSELF! Practical Applications 1. If the scores in a certain test have a mean of 500 and a standard deviation of 100, what percent of the scores are: a) Between 400 and 600? b) Greater than 650? c) Less than 300? 2. A popular picture shown in a theater for a month drew a big crowd of moviegoers, giving a daily mean of 600 persons and a standard deviation of 80 persons. Find the following: a) The probability that attendance figures will be greater than 750 b) The value below which we will find the lowest 40% of these attendance figures