Control Group Design

Please respond to the following questions either by writing the design name or by describing the design using standard notation (X = program, O=observation, R= random assignment). For each design, please discuss all threats to internal validity.

1. a. Design: Single group post-test only

b. Internal validity threats:

2. a. Design: (R) O1 X O2

(R) O1 O2

b. Internal validity threats:

3. a. Design: Pretest-posttest design with experimental and comparison group

b. Internal validity threats:

4. a. Design: O X O

b. Internal validity threats:

5. a. Design: Single group with three pretests and four posttests

b. Internal validity threats