Chapter 4, Problem 1DH

Look at Figure 4-11, Who’s Cracking the Books?

1. (a) Does the figure show the probability distribution of grade records for male students? for female students? Describe all the grade-record probability distributions shown in Figure 4-11. Find the probability that a male student selected at random has a grade record showing mostly As.

1. (b) Is the probability distribution shown for all students making mostly As? Explain your answer. Hint: Do the percentages shown for mostly As add up to 1? Can Figure 4-11 be used to determine the probability that a student selected at random has mostly As? Can it be used to determine the probability that a female student selected at random has mostly As? What is the probability?
2. (c) Can we use the information shown in the figure to determine the probability that a graduating senior has grades consisting of mostly Bs or higher? What is the probability?
3. (d) Does Figure 4-11 give sufficient information to determine the probability that a student selected at random is in the age range 19 to 23 and has grades that are mostly Bs? What is the probability that a student selected at random has grades that are mostly Bs, given that he or she is in the age range 19 to 23?
4. (e) Suppose that 65% of the students at State University are between 19 and 23 years of age. What is the probability that a student selected at random is in this age range and has grades that are mostly Bs?