Statistics: Bias and Sampling Flashcards

These flashcards cover the definitions, examples, and distinctions between different types of bias and sampling errors as described in the lecture notes.

When is bias introduced in a statistical method?

Bias is introduced when a method systematically favors certain outcomes over others, making it very likely to underestimate or overestimate the value you want to know.

In a Free Response Question (FRQ), what two components should you always include when identifying bias?

You should always pick a direction with a reason.

What is voluntary response bias?

Voluntary response bias occurs when people self-select themselves as part of a study. It typically attracts individuals who feel strongly about an issue (often with negative opinions) and who are not representative of the population.

What is question wording bias?

Question wording bias occurs when survey questions are confusing or lead the person taking the survey to answer in a certain way, such as asking, "Do you think it's OK for toddlers to eat unhealthy candy?"

What is undercoverage in sampling?

Undercoverage occurs when some members of the population are less likely to be chosen in a sample, often because the sampling frame is inaccurate or incomplete.

What is a sampling frame?

A sampling frame is a list of individuals in the population from which the sample is actually selected.

What are examples of groups often left out due to undercoverage in household samples?

Homeless people, prison inmates, and students in dormitories.

What is nonresponse?

Nonresponse occurs when an individual chosen for the sample cannot be contacted or refuses to participate, and these people would respond differently from those who do participate.

When can nonresponse occur in relation to sample selection?

Nonresponse can occur only after a sample has been selected. It does not occur in voluntary response samples because every individual has already opted to take part.

What is response bias?

Response bias occurs when there is a systematic pattern of inaccurate answers to a survey question.

What are some reasons for response bias to occur?

Individuals may lie about sensitive topics (age, income, drug/alcohol use), make up answers to questions they do not understand, or be influenced by the interviewer's behavior.