In a study using a true experimental design, which of these ...

[kshipps]

In a study using a true experimental design, which of these methods would control for antecedent variables?
 
  a. Manipulation of the independent variable
  b. After-only data collection
  c. Intervention fidelity
  d. Random assignment to groups

Question 2

What type of threat to validity is minimized by the use of a Solomon four-group design?
 
  a. Mortality
  b. Selection bias
  c. Testing
  d. Antecedent variable

[Juro]

Answer to Question 1

ANS: D

Feedback
A Manipulation of the independent variable cannot control a factor that occurred before the study.
B After-only data collection would not control preexisting variables.
C Systematically delivering the intervention would not control preexisting variables.
D Random assignment to groups helps ensure that antecedent (preexisting) variables will be similarly distributed between groups.

Answer to Question 2

ANS: C

Feedback
A Use of four groups does not control subject mortality (attrition rate).
B The Solomon four-group design will not by itself minimize selection bias. Strict selection criteria and random assignment to groups are necessary to minimize selection bias.
C Testing threats to internal validity are minimized by the Solomon four-group design.
D Because antecedent variables such as motivation to learn existed prior to the study, they should be identified and measured before the study; differences can be statistically controlled. The Solomon four-group design, however, does not control antecedent variables.