According to a study released by the federal Substance Abuse and Mental Health Services Administration (Knight Ridder Tribune, September 9, 1999), approximately 8% of all adult full-time workers are drug users and approximately 70% of adult drug users are employed full-time.

a. Is it possible for both of the reported percentages to be correct? Explain.

b. Define the events D and E as D = event that a randomly selected adult is a drug user and E = event that a randomly selected adult is employed full-time. What are the estimated values of P(D|E) and P(E|D)?

c. Is it possible to determine P(D), the probability that a randomly selected adult is a drug user, from the information given? If not, what additional information would be needed?