CNN staff writer Pariia Bhatnagar reported (“Coke, Pepsi Losing the Fizz,” March 8, 2005) that Atlanta-based Coke saw its domestic market share drop to 43.1% in 2004. New York-based PepsiCo had used its “Pepsi Challenge” advertising approach to increase its market share, which stood at 31.7% in 2004. A selection of soft-drink users is asked to taste the two disguised soft drinks and indicate which they prefer. The file titled Challenge contains the results of a simulated Pepsi Challenge on a college campus.
a. Determine the probability that a randomly chosen student prefers Pepsi.
b. Determine the probability that one of the students prefers Pepsi and is less than 20 years old.
c. Of those students who are less than 20 years old, calculate the probability that a randomly chosen student prefers (1) Pepsi and (2) Coke.
d. Of those students who are at least 20 years old, calculate the probability that a randomly chosen student prefers (1) Pepsi and (2) Coke.