Chapter 6.3, Problem 109E

College-Math Success. Researchers S. Lesik and M. Mitchell explore the difficulty of predicting success in college-level mathematics in the article “The Investigation of Multiple Paths to Success in College-Level Mathematics” (Journal of Applied Research in Higher Education, Vol. 5, Issue 1, pp. 48–57). One of the variables explored as an indicator of success was the length of time since a college freshman has taken a mathematics course. The article reports that the mean length of time is 0.18 years with a standard deviation of 0.624 years. For college freshmen, let x represent the time, in years, since taking a math course.

1. a. What percentage of times are at least 0 years?
2. b. Assuming that x is approximately normally distributed, use normal-curve areas to determine the approximate percentage of times that are at least 0 years.
3. c. Based on your results from parts (a) and (b), do you think that the length of time since taking a math course for college freshmen is approximately a normally distributed variable? Explain your answer.