6.69 The report “Twitter in Higher Education: Usage Habits and Trends of Today’s College Faculty” (Magna Publications, September 2009) describes results of a survey of nearly 2000 college faculty. The report indicates the following:

● 30.7% reported that they use Twitter and 69.3%

said that they did not use Twitter.

● Of those who use Twitter, 39.9% said they sometimes use Twitter to communicate with students.

● Of those who use Twitter, 27.5% said that they sometimes use Twitter as a learning tool in the classroom.
Consider the chance experiment that selects one of the study participants at random and define the following events:
T 5 event that selected faculty member uses Twitter C 5 event that selected faculty member sometimes uses Twitter to communicate with students L 5 event that selected faculty member sometimes uses Twitter as a learning tool in the classroom

a. Use the given information to determine the following probabilities:
i. PsTd ii. PsTC d iii. PsCuTd iv. PsLuTd v. PsC > Td

b. Interpret each of the probabilities computed in Part (a).

c. What proportion of the faculty surveyed sometimes use Twitter to communicate with students? [Hint:
Use the law of total probability to find P(C).]

d. What proportion of faculty surveyed sometimes use Twitter as a learning tool in the classroom?