Stats: Evaluation Content and Structure Flashcards

A researcher surveys every 10th student on an alphabetical class roster. What type of sampling method is this?

Answer: Systematic sampling

Systematic sampling selects every kth element from an ordered list after a random start.

Which of the following best describes a confounding variable in an experiment?

Answer: A variable related to both the explanatory and response variable that can distort results

A confounding variable is associated with both the explanatory variable and the response, making it hard to determine causation.

In an observational study comparing incomes of college graduates vs. non-graduates, why can't we conclude that college causes higher income?

Answer: Lurking variables such as family background may explain the difference

Observational studies cannot establish causation because lurking variables may drive any observed association.

A study randomly assigns participants to treatment and control groups. This design feature primarily controls for:

Answer: Confounding variables

Random assignment balances both known and unknown confounding variables across treatment groups.

Which of the following is an example of a double-blind experiment?

Answer: Neither the subjects nor the researchers know who received which treatment

Double-blind means both participants and those measuring outcomes are unaware of treatment assignments.

A poll asking 'Don't you agree that texting while driving is dangerous?' is an example of:

Answer: Response bias due to leading question wording

The phrasing 'Don't you agree' leads respondents toward a particular answer, causing response bias.

A study finds a strong positive correlation (r = 0.92) between shoe size and reading scores in elementary students. The most plausible explanation is:

Answer: Age is a lurking variable explaining both

Older children have both larger feet and higher reading scores, making age the lurking variable driving this correlation.