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:
http://www.jiskha.com/display.cgi?id=1327839775
please answer the question above
1. a. Design: Single group post-test only
b. Internal validity threats: The main threat to internal validity in this design is the lack of a comparison or control group. Without a comparison group, it is difficult to determine if any changes observed in the post-test are truly due to the intervention or if they could be due to other factors like maturation, history, or regression to the mean.
2. a. Design: (R) O1 X O2 (R) O1 O2
b. Internal validity threats: One potential threat in this design is selection bias. If the random assignment of participants to the experimental and control groups is not done properly, there may be systematic differences between the two groups that could affect the results. Another threat is the lack of a pretest in the control group. Without a pretest, it is hard to establish baseline equivalence between the groups, making it difficult to attribute any observed differences solely to the intervention.
3. a. Design: Pretest-posttest design with experimental and comparison group
b. Internal validity threats: There are several potential threats in this design. One is selection bias, where the experimental and comparison groups may differ systematically at the outset. Another threat is history, where any external events or factors that occur during the study could influence the outcomes. Maturation is also a concern, as participants in both groups may naturally change over time. Additionally, there could be testing effects or instrumentation threats if the pretest sensitizes participants to the treatment or if the measurement instruments are not reliable or valid.
4. a. Design: O X O
b. Internal validity threats: The main threat in this design is the lack of a control or comparison group. Without a control group, it is difficult to determine if any changes observed in the post-test are truly due to the intervention or if they could be due to other factors like maturation, history, or regression to the mean.
5. a. Design: Single group with three pretests and four posttests
b. Internal validity threats: One potential threat in this design is the lack of a comparison or control group. Without a comparison group, it is difficult to determine if any changes observed in the post-tests are truly due to the intervention or if they could be due to other factors like maturation, history, or regression to the mean. Additionally, there may be testing effects, where the repeated pretests or posttests could influence participants' responses or behavior.