What is the regression threat in a single group design? What ...

[theo]

What is the regression threat in a single group design?
 
  What will be an ideal response?

Question 2

In a multiple-baseline design
 
  a. the length of the baseline period is the same for all of the subjects in the experiment.
  b. the behavior of the subjects is expected to revert to baseline levels after the removal of the independent variable.
 c. the length of the baseline period is different for different subjects or different behaviors prior to the introduction of the independent variable.
 d. the occurrence of carryover effects cannot be assessed.

[Mochi]

Answer to Question 1

A regression threat to internal validity, also known as a regression artifact or regression to the mean, is a statistical phenomenon that falsely makes it appear that your group changed to be more like the overall population between the pretest and posttest. If your group was above the population average on the pretest, they will look like they lost ground on the posttest. If they were below the population average on the pretest, they will falsely appear to improve. Regression occurs whenever you have a nonrandom sample from a population and two measures that are imperfectly correlated.

Answer to Question 2

C