1. In a survey conducted by AOL and the Associated Press, less than 25% of adults use instant messaging (IM), and almost 75% of adults who use IM use e-mail more often than IM. The survey also showed that almost 50% of teens use IM, and almost 75% of teens who use IM use IM more often than e-mail (M. Levitt, "Bridging the Collaboration Age Gap with Unified Communications and Web 2.0," KM World, June 2007, p. 10).

a. What other information would you want to know before you used the results of this survey?

b. Suppose you work for AOL and wanted to investigate IM and e-mail usage by AOL users. Define the population, frame, and sampling method you would use.

2.An average of 15 aircraft accidents occur each year (The World Almanac and Book of Facts, 2004).

a. Compute the mean number of aircraft accidents per month.

b. Compute the probability of no accidents during a month.

c. Compute the probability of exactly one accident during a month.

d. Compute the probability of more than one accident during a month.