The increase in Internet usage over the past few years has been phenomenal, as demonstrated by the February 2004 report from the Pew Internet & American Life Project. The survey of Americans 65 or older (about 8 million adults) reported that 22% have access to the Internet. By contrast, 58% of 50 to 64-year-olds, 75% of 30- to 49-year-olds, and 77% of 18- to 29-year-olds currently go online. Suppose that 50 adults in each age group are to be interviewed.
a. What is the probability that “have Internet access” is the response of 10 to 20 adults in the 65 or older group?
b. What is the probability that “have Internet access” is the response of 30 to 40 adults in the 50- to 64-year-old group?
c. What is the probability that “have Internet access” is the response of 30 to 40 adults in the 30- to 49-year-old group?
d. What is the probability that “have Internet access” is the response of 30 to 40 adults in the 18- to 29-year-old group?
e. Why are the answers for parts a and d nearly the same? Explain.
f. What effect did the various values of p have on the probabilities? Explain.