Question

political pollsters now make sure to conduct a percentage of their telephone interviews by calling mobile phones. this policy best addresses which potential source of bias?

• some of the population may not have access to other types of phones.
• the survey only reaches individuals who volunteer to be interviewed.
• the policy helps individuals understanding the wording of survey questions.
• some individuals contacted may choose to not participate.

Explanation:

To determine the correct answer, we analyze each option:

• Option 1: If some people don't have access to non - mobile phones (like landlines), only calling landlines would miss them. By including mobile phones, pollsters address this sampling bias from lack of access to certain phone types.
• Option 2: Volunteer bias is about people self - selecting to be surveyed, and calling mobile phones doesn't relate to this.
• Option 3: Calling mobile phones doesn't help with understanding survey questions' wording.
• Option 4: Non - participation bias is about people choosing not to participate after being contacted, and calling mobile phones doesn't address this.

So the correct option is the one about access to other phone types.

Answer:

A. Some of the population may not have access to other types of phones.