A March 2010 SurveyUSA telephone poll on issues facing central Ohio contacted a random sample of 500 households in the Columbus, Ohio, area. One question was "Where 10 means most important, and 1 means least important, how important is protecting the environment?" The average response was 6.0. Which population is the poll targeting? all households in the Columbus area registered voters in the Columbus area the 500 households in the Columbus area who responded all households with a strong opinion on the environment in the Columbus area