Question

Identify the type of bias in each scenario(2 points)
voluntary response bias sample bias measurement error
a poll conducted on a website where only frequent visitors respond



a survey asking people to estimate their weekly calorie intake



a survey mailed to residents, but only retirees respond



a company surveys only its most loyal customers

Answer 1

1) A poll on a website where only frequent visitors respond — voluntary response bias (self-selection by frequent visitors).

2) A survey asking people to estimate their weekly calorie intake — measurement error (inaccurate self-report/recall).

3) A survey mailed to residents, but only retirees respond — voluntary response bias (nonresponse leads to a nonrepresentative respondent set).

4) A company surveys only its most loyal customers — sample bias (the chosen sample excludes typical/less-loyal customers).