Based on a USA Today poll, assume that 10% of the population believes that college is no longer a good investment.
a. Find the probability that among 16 randomly selected people exactly 4 believe that college is no longer a good investment.
b. Find the probability that among 16 randomly selected people, at least 1 believes that college is no longer a good investment.
c. The poll results were obtained by Internet users logged on to the USA Today web site, and the Internet users decided whether to ignore the posted survey or respond. What type of sample is this? What does it suggest about the validity of the results?