marshpa
A recent research study of undergraduate students analyzed the effects of music on human emotions. Each of the 200 participants attended at least 1 two-hour concert of classical music per week over the course of 12 weeks of their spring semester. At the end of the experiment, all of the students filled out a questionnaire assessing their emotional state. Based on the results of the questionnaires, all of the 10 students who attended the greatest number of concerts reported lower stress levels and higher satisfaction with their lives. Also, most of the 20 students who attended the fewest number of concerts reported below-average levels of emotional comfort.
Which of the following must be true based on the evidence presented above?
(A) Most of the 200 participants improved their emotional state and lowered their stress levels.
(B) During each week of the experiment, the participants spent at least 2 hours less on their academic work as a result of concert attendance.
(C) Listening to classical music for at least 2 hours per week improves the emotional well-being of the majority of young adults.
(D) More than 6 participants attended at least 14 concerts during the course of the experiment.
(E) At least some of the students participated in the study in order to gain free access to classical concerts.
OFFICIAL EXPLANATION
The argument above provides a detailed description of a research study. Note that the question stem contains only factual information and does not have a conclusion. Our task is to provide the most probable conclusion for this argument, i.e. the one that must be true based on the provided evidence. When looking for the most probable conclusion, remember not to make any additional assumptions and choose the answer that directly follows from premises stated in the argument.
(A) This statement does not have to be true. The argument provides evidence about the emotional progress of only 30 participants. The fact that we have no information about the vast majority of participants demonstrates that the statement in this answer choice cannot be justified.
(B) While each participant did spend at least 2 hours each week attending the concerts, there is no information in the argument that would suggest that the students reduced their study time. For example, they could have attended the concerts in their free time.
(C) This statement does not have to be true, since we have no information about the emotional progress of the vast majority of study participants. Note that even if the study did demonstrate a positive effect of classical music on the majority of participants, it would still be uncertain whether this effect would hold for the majority of young adults.
(D) CORRECT. We know that 20 students attended the fewest number of concerts, 10 students attended the greatest number of concerts, and the remaining 170 students attended some other number of concerts in between. The term 'greatest' indicates that there are at least 3 different numbers of concerts attended by the students (as opposed to 'greater' to distinguish between 2 different numbers). Since each of the participants attended at least one concert per week during the 12 weeks of the experiment, all of the study participants must have attended at least 12 concerts. Even if the 20 bottom students attended the smallest possible number of concerts (i.e. 12), it must be the case that the next 170 students in the middle attended at least one more (i.e. at least 13 concerts) and the 10 most active participants must have attended at least one more than the middle group, i.e at least 14 concerts. Thus, it must be true that the 10 most active participants (i.e. more than 6 participants) attended at least 14 concerts, as stated in this answer choice. Note that if the students attended more concerts than the minimum requirement, the number of students with at least 14 concerts attended will be even greater, still validating the accuracy of this statement.
(E) The argument does not explicitly state whether the participants received free access to the concerts or had to pay for admission (e.g. they could have just received a discount). In addition, no information is provided about the motivation of study participants.