1. Look at Figure 4-11, “Who’s Cracking the Books?”

(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 A’s.

(b) Is the probability distribution shown for all students making mostly A’s?
Explain your answer. Hint: Do the percentages shown for mostly A’s add up to 1? Can Figure 4-11 be used to determine the probability that a student selected at random has mostly A’s? Can it be used to determine the probability that a female student selected at random has mostly A’s? What is the probability?

(c) Can we use the information shown in the figure to determine the probability that a graduating senior has grades consisting of mostly B’s or higher?
What is the probability?

(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 B’s? What is the probability that a student selected at random has grades that are mostly B’s, given that he or she is in the age range 19 to 23?

(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 B’s?

Transcribed Image Text:

Undergraduate Grade Record by Student Characteristic C's and D's B's and Student characteristic or lower C's Mostly B's A's and B's Mostly A's Gender: Men 38.8 % 16.6 % 22.6 % 9.6 % 12.4 % Women 29.4 16.2 26.2 12.0 16.2 Class level: Graduating senior 15.8 % 21.9% 34.5 % 14.7 % 13.0 % All other class levels 35.4 15.8 23.6 10.5 14.7 Age: 18 or younger 42.6 % 14.7 % 23.4 % 9.4 % 10.0% 19 to 23 38.11 19.0 25.1 9.4 8.3 24 to 29 33.3 16.9 24.7 10.3 14.9 30 to 39 23.1 13.2 25.9 14.8 23.0 40 and older 20.1 10.1 22.0 14.8 33.0 Source: U.S. Department of Education