Question

Are highly unreliable in part because people who have strong opinions are more likely to participate.

Answer 1

The answer is "voluntary response surveys"

Explanation:

It was asked to fill in the blank so that this sentence makes a sense. Hence, the statement becomes, "Voluntary response surveys are highly unreliable in part because people who have strong opinions are more likely to participate."

This is due to the fact that these surveys do not specify the people involved in it. Some people are more vocal others are not. Hence, we can not solely depend on the result to these surveys to reach to a conclusion .

Answer 2

Explanation:

Voluntary Response Surveys