Question

Which of the following is a reason that a researcher might choose a pretest/posttest design?

Group of answer choices
to determine between-group differences
to ensure that random assignment made the treatment/comparison groups equal
to improve construct validity
to allow for the study of spontaneous behaviors

Answer 1

A pretest/posttest design is chosen to ensure equal groups, improve construct validity, and study spontaneous behaviors in research.

Step-by-step explanation:

A researcher might choose a pretest/posttest design for several reasons. One reason is to ensure that random assignment made the treatment/comparison groups equal. This design allows the researcher to compare the groups' performance before and after the treatment, which helps determine the effectiveness of the treatment. Another reason is to improve construct validity. By measuring the outcome variable both before and after the treatment, the researcher can ensure that any changes observed are truly due to the treatment and not due to other factors. Lastly, using a pretest/posttest design also allows for the study of spontaneous behaviors. Observing and measuring behavior over time can provide insights into how individuals naturally respond and change over time.

Answer 2

A pretest/posttest design is used to ensure that random assignment has made comparison groups equal, allowing for the establishment of a causal connection between the independent and dependent variables.

Step-by-step explanation:

A researcher might choose a pretest/posttest design to ensure that random assignment made the treatment/comparison groups equal at the start of an experiment. Random assignment is crucial in this design to balance out any potentially confounding variables (lurking variables) across the groups, so that any differences observed in the posttest can likely be attributed to the manipulation of the independent variable. This method essentially controls for preexisting differences, allowing for a causal connection between the independent and dependent variables to be established when evaluating the efficacy of interventions, such as a new math textbook.

Therefore, Option b is correct answer.