Mobile access to social media. The Marketing Management Journal (Fall 2014) published the results of a designed study to investigate satisfaction with the use of mobile devices to access social media. Mobile device users were classified by gender (male or female) and by the social media they use most often (Facebook, Twitter, or YouTube). Consider a similar study in which 10 males and 10 females were sampled for each of the three social media—a total of 60 mobile device users. One of these users is randomly selected. Of interest is his or her gender and most used social media.

a. Use a tree diagram to determine the possible outcomes (sample points) for this experiment.

b. Why should the probabilities assigned to each outcome be equal? Give the value of this probability.

c. Find the probability that the selected user is a female who accesses Twitter most often.

d. Find the probability that the selected user accesses YouTube most often. Applying the Concepts—Intermediate