MCAT Math Question 43: Answer and Explanation

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Question: 43

13. A new medication for heart failure is being developed and has had a statistically significant effect on contractility in clinical trials. Which of the following would NOT likely cause the drug to be held back from common use?

  • A. The value of α used was 0.5.
  • B. Similar compounds display toxicity.
  • C. The effect size is clinically insignificant.
  • D. The study had low power to detect a difference.

Correct Answer: D

Explanation:

If a study has low power, it is more difficult to get results that are statistically significant. Therefore, if the results are still statistically significant even with low power, then there is likely a large effect size that makes the effect clinically significant. If the value of α used in the study was 0.5, then statistically significant results do not mean much—traditionally, α = 0.05 or a smaller probability is used, eliminating choice (A). Concerns about toxicity should always limit the use of a drug, eliminating choice (B). A statistically significant result is only of interest if it also represents a clinically significant improvement, eliminating choice (C).

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