Following a Senatorial Election in California, a Los Angeles Times

Essay

Following a senatorial election in California, a Los Angeles Times article pointed out that the polls are not as reliable as media portrayals would suggest. The author gave several examples of seemingly contradictory poll results in pre-election surveys; for example, one poll had one candidate ahead by 10 points and another poll had her trailing by 2. Suppose someone asks you to explain how this could occur. Assuming that all the polls were telephone surveys that used probability sampling, identify and briefly describe three possible sources of sampling error in the polls.