Therapist: In a recent study, researchers measured how quickly 60 different psychological problems waned as a large,...

Kath on October 30, 2019


I am so weak on the statistical problems. Could you explain this question and give me some short-cuts?

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Annie on November 3, 2019

Hi @Kath,

Good question! Statistical problems are tricky mainly because they are throwing numbers at you. But, when you break down the problem, they're actually just the same as any other logical reasoning question. What I find helpful is to separate out the argument parts. Here, we have:

Premise: A recent study found that about 75% of 60 different psychological problems were cleared up with 50 weeks of therapy.
Conclusion: 50 weekly behavioral therapy sessions are all that most people need.

This question is asking you to find the vulnerability in the argument. So, you want to find what logical step is missing between the premise and conclusion.

Answer Choices:
(A) is incorrect. This is a tricky answer. The key here though is that the answer is talking in absolutes ("no psychological problems") while the argument uses words like most. Even if there is 1 problem that will take longer to clear up, it still may be true that most people only need 50 sessions.

(B) is correct. This answer choices focuses on the gap between the premise and the conclusion. There is a chance that most people are afflicted by an issue which takes longer than 50 weeks to cure, as only 75% of 60 issues were found to be cured with 50 weeks of therapy.

(C) is incorrect. There is no discussion of someone having multiple psychological problems.

(D) is incorrect. There is no discussion of whether certain types of therapy are less effective.

(E) is incorrect. The therapist states that a "large, diverse sample of people" were included in the study. There is no indication that the group was no representative of the population as a whole.