A Washington Post/ Kaiser Family Foundation poll taken July 25 to August 5, 2012, asked a random sample of 3130 adults: “Do you support or oppose putting a special tax on junk food—that is, things like soda, chips, and candy—and using the money for programs to fight obesity?” They reported that 53% of the respondents said “Support” and that the margin of error for the poll was ± 2 percentage points. (Source: www.pollingreport.com/ food. htm, accessed May 13, 2013.)
a. Verify that the reported margin of error of ± 2 percentage points is correct (rounded to a whole number of percentage points).
b. What is the numerical interval that is likely to cover the true percentage of the entire population that would have answered “Support” if asked at that time?
c. Refer to the seven pitfalls in Chapter 3 (listed on page 42) that might be encountered when asking questions in a survey. Which one of them might have been a problem for this survey question? Explain.