THE NORMAL CURvE SECTION 12.5 EXTRA PRACTICE 1. If a given piece of data has a negative z-score, is the given piece of data above the mean or below the mean? 2. Suppose a data set has a mean of 22.5 and a standard deviation of 5. Determine the z-score for a data point with value 19. 3. Assume that the number of hours that college students spend working per week Is norrnallvI distributed with a mean of 18 hours and a standard deviation of 4 hours. a. Determine the percentage of college students who work at lea st 13 hours per week. In. Determine the percent of college students who work between 14 and 26 hours per week. c. Determine the percent of college students who work at least 24 hours a week. d In a random sample of SDI} college students, how man},r work at least 24 hours per week