When surveyed about which party they would like to see in the legislature, 40 percent of respondents said Conservative, 20 percent said Moderate, and 40 percent said Liberal
If the survey results are reliable, we can conclude that most citizens would like to see a legislature that is roughly 40 percent Conservative, 20 percent Moderate, and 40 percent Liberal
The argument takes for granted that the preferences of a group as a whole are the preferences of most individual members of the group.