Results for this survey are based on telephone interviews conducted under the direction of Princeton Survey Research Associates International among a nationwide sample of 1,508 adults, 18

years of age or older, from April 18-22, 2007. For results based on the total sample, one can say with 95% confidence that the error attributable to sampling is plus or minus 3 percentage

points. For results based on parents of children in school (N=359) or college (N=215), one can say with 95% confidence that the error attributable to sampling is plus or minus 6 and 7.5

percentage points, respectively. In addition to sampling error, one should bear in mind that question wording and practical difficulties in conducting surveys can introduce error or bias