Nutritionist: A recent nutrition study confirms that nutritious breakfasts increase GMAT test taker’s final score. For one month, test takers in Group A received free nutritious breakfasts every day before their intense study, while test takers in Group B did not. At the end of the month, both groups took the same GMAT test. The average score of Group A’s test takers increased, while that of Group B’s test takers did not.
Which one of the following, if true, most strengthens the argument?
A) During the month before the study, test takers at Group A and Group B had similar average GMAT scores. B) Test takers in the study from Group A and Group B started studying at the same time of day at the same location. C) Few test takers in Group B consumed equally nutritious breakfasts during the month of the study. D) Test takers from Group A took fewer days off per person during the month of the study than did test takers from Group B. E) Test takers in Group A visited www.chasedream.com more often during the month of the study than did test takers from Group B.
A is an attractive answer since it seems to make the battlefield even and make sure the fight fair. However, a similar starting point is not required for the argument. For example, if Group A increased from 700 to 730 while Group B remained at 620, the argument still holds. An increase is an increase no matter how high or how low the starting point. So answer A has no overall effect on the argument since we are not comparing Group A with Group B. Instead we are comparing changes made within Group A and those within Group B. Notice the difference between these two scenarios?
Vote for C ? Though not sure. Both A&B look attractive, in that they instate that nothing else would likely to contribute to GroupB's performance. C stands out for indicating that the breakfast is precisely the reason why B did a better job.
C is the correct answer. If members of Group B also ate nutritious breakfast, the argument falls apart since members of Group B have no improvemnet in their GMAT scores.
You did not understand your own statement. C simply removed the possibility of B ate breakfast. Thus C removes one scenario of weakening the hypothesis and makes the argument more likely.