A group of researchers wanted to study United States citizens' perception on assault rifle ownership. To generate their sample, they identified all towns of 1000 people or fewer in the U.S., randomly selected 20 of those towns, and mailed a total of 4500 surveys to every household in those towns. The survey asked, "With the recent increase in gun violence incidents, would you support a nationwide ban on assault rifles?"; it also included a stamped return envelope so that participants could return the survey at no cost to themselves. Of the 1281 responses, 28% of the respondents answered the survey with a "yes