PUBH 6235 Week 8: Study Design/Internal Validity 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:
