Cette étude a été menée par RoperASW via OmniTel, a weekly national telephone omnibus service. The sample consists of 1,021 male and female adults (in approximately equal number), all 18 years of age and over.
The telephone interviews were conducted from August 23 through August 25, 2002, using a Random Digit Dialing (RDD) probability sample of all telephone households in the continental United States.
Interviews were weighted by five demographic factors: age, sex, education, race and geographic region. Weights were applied to ensure accurate representation of the adult population in each of these areas.
The margin of error for the total sample is +/- 3 percent.