Week 6

Question 1

What is an example of a really bad but common experiment design?

Answer 1

One-group pre-test post-test design.

Question 2

What are the six threats to internal validity?

Answer 2

Maturation; history; regression; attrition; testing; instrumentation.

Question 3

What are maturation threats to internal validity?

Answer 3

Participants may improve over time regardless of the study.

Question 4

What are history threats to internal validity?

Answer 4

Specific events which occur between the first and second measurement.

Question 5

What are regression threats to internal validity?

Answer 5

Regression to the mean; within subject effect; when a performance is extreme at Time 1, the next time that performance is measured is likely to be less extreme.

Question 6

What are attrition threats to interval validity?

Answer 6

Participants that drop out of the study.

Question 7

What are testing threats to internal validity?

Answer 7

The effects of taking a test on the outcomes of taking a second test.

Question 8

What are instrumentation threats to internal validity?

Answer 8

The change in the instrument, observers or scorers which may produce changes in outcomes.

Question 9

What could it mean if the independent variable does not make a difference?

Answer 9

Not enough between-groups difference; within-groups variability obscured the group differences; there is really no difference.