Chapter 8.1, Problem 25E

To determine

To identify which is the possible source of bias included in the $\pm 2$ % margin of error.

Answer to Problem 25E

None of these.

Explanation of Solution

Given:

I. Some people refused to answer.

II. People without telephones could not be in the sample.

III. Some people never answered the phone in several calls.

We know that, margin of error only contains sampling error. That is, after collection of data.

Option I isnonresponse biaswhich is NOT a sampling error. Option II is a selection bias which is NOT a sampling error. Option III is non-response bias, which is NOT a sampling error. Hence, none of these is included in margin of error.