A March 2010 Survey USA Telephone Poll on Issues Facing

Multiple Choice

A March 2010 Survey USA 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 of the following is NOT a likely source of error in this survey?

A) Nonresponse
B) Question wording
C) Undercoverage from the need to have a telephone
D) Bias from a voluntary response sample