The Associated Press-GfK poll on the Super Bowl and the NFL was conducted by GfK Public Affairs and Corporate Communications Jan. 17-21. It is based on online interviews of 1,060 adults who are members of GfK's nationally representative KnowledgePanel.
The original sample was drawn from a panel of respondents recruited via phone or mail survey methods. GfK provides Internet access to panel recruits who don't already have it. With a probability basis and coverage of people who otherwise couldn't access the Internet, online surveys using KnowledgePanel are nationally representative.
Interviews were conducted in both English and Spanish.
As is done routinely in surveys, results were weighted, or adjusted, to ensure that responses accurately reflect the population's makeup by factors such as age, sex, race, education and phone usage.
No more than 1 time in 20 should chance variations in the sample cause the results to vary by more than plus or minus 3.9 percentage points from the answers that would be obtained if all adults in the U.S. were polled. For results among the 554 fans of professional football interviewed, the margin of sampling error is plus or minus 5.4 percentage points.
The poll had a cooperation rate of 48 percent.
There are other sources of potential error in polls, including the wording and order of questions.
The questions and results are available at http://www.ap-gfkpoll.com .