Are you feeling stressed? (4.1) A Gallup Poll asked whether people experienced stress “a lot of the day yesterday.” About 41 percent said they did. Gallup’s report said, “Results are based on telephone interviews conducted … Jan. 1–Dec. 31, 2012, with a random sample of 353,564 adults aged 18 and older.”5

(a) Identify the population and the sample.

(b) Explain how undercoverage could lead to bias in this survey.