Question

a study was conducted to compare two biology study aids: a new online game and physical flashcards. 80 middle school biology students were selected at random, and their parent(s) chose which study aid their child used. the results showed that the students who used flashcards had significantly better outcomes than students who used the online game. based on this information, which of the following statements is true? choose 1 answer: a flashcards are a more effective study aid than the online game for all middle school biology students. b the lack of random assignment means there could be other explanations for the study results. c the lack of a control group makes comparing flashcards and the online game impossible

Explanation:

• Option A: The study only involved 80 middle - school biology students. We cannot generalize the result to "all middle - school biology students" just based on this sample. There could be other factors in students not in the sample that affect the effectiveness of the study aids.
• Option B: In an experiment, random assignment helps to balance out other variables (confounding variables) between the groups. Since the parents chose the study aid (not random assignment), there could be differences between the two groups (e.g., parents who choose flashcards might be more involved in their child's study in other ways, which could affect the outcome). So, the lack of random assignment means there could be other explanations for the results.
• Option C: There is no control group (a group that uses no study aid, for example). But the problem is about comparing two study aids (flashcards and online game). A control group is not necessary for comparing two treatment groups (the two study aids in this case).

Answer:

B. The lack of random assignment means there could be other explanations for the study results.