At its website (www.gallup.com), the Gallup Poll publishes results of a new survey each day. Scroll down to the end, and you’ll find a statement that includes an explanation such as this:

Results are based on telephone interviews conducted April 1-30, 2017, with a random sample of 30,401 adults, aged 18 and older, living in all 50 U.S. states and the District of Columbia.

a) For this survey, identify the population of interest.

b) Gallup performs its surveys by phoning numbers generated at random by a computer program. What is the sampling frame?

c) What problems, if any, would you be concerned about in matching the sampling frame with the population?