Author Question: People who are cannot be contacted or who refuse to participate in a survey are called ... (Read 82 times)

big1devin · **on:** Jun 28, 2018

People who are cannot be contacted or who refuse to participate in a survey are called ___________________ _.
Fill in the blank(s) with correct word

Question 2

When the people who answer a mail survey are different in important ways (e.g., income level) from the people who did not answer the survey, the survey is said to have ___________________ _ error.
Fill in the blank(s) with correct word