a. How do true experimental designs control for threats to external validity? What are some concerns you might have?
b. Are quasi-experimental designs more or less useful than true experimental designs in determining the external validity of the investigation? Why or why not?
c. What type of design is recommended if you are concerned that males and females have different attitudes toward math and may perform differently in math? Why?
d. What type of design have you used when you pretest a single class, provide the instruction, then posttest the class? What are the problems with this design? What conclusions could you make in terms of internal and external validity?