In an experiment, two different types of recorded

[B BTGmoderatorDC]

In an experiment, two different types of recorded music were played for neonates in adjacent nurseries in a hospital. In nursery A, classical music was played: in nursery B, rock music was played. After two weeks, it was found that the babies in nursery A cried less, suffered fewer minor ailments, and gained more weight than did the babies in nursery B.

In evaluating the validity of the conclusion suggested by the experiment above it would be most important to know which of the following?
A) The musical preferences of the parents of the two groups of newborns.
B) Whether the newborns in both the nurseries were equally healthy and happy at the start of the experiment.
C) Whether loud rock music can damage the hearing of newborns.
D) what the average weight of the neonates was before and after the experiment
E) Whether the music was played in the nurseries at all times or only at certain times.

[GMATGuruNY]

In an experiment, two different types of recorded music were played for neonates in adjacent nurseries in a hospital. In nursery A, classical music was played: in nursery B, rock music was played. After two weeks, it was found that the babies in nursery A cried less, suffered fewer minor ailments, and gained more weight than did the babies in nursery B.

In evaluating the validity of the conclusion suggested by the experiment above it would be most important to know which of the following?

A) The musical preferences of the parents of the two groups of newborns.
B) Whether the newborns in both the nurseries were equally healthy and happy at the start of the experiment.
C) Whether loud rock music can damage the hearing of newborns.
D) what the average weight of the neonates was before and after the experiment
E) Whether the music was played in the nurseries at all times or only at certain times.

Experiment:
In nursery A, classical music was played; in nursery B, rock music was played.
Result:
The babies in nursery A cried less, suffered fewer minor ailments, and gained more weight than did the babies in nursery B.

Implied conclusion:
The babies in nursery A had better outcomes because of the type of music played in nursery A.

The correct answer must help us evaluate the implied conclusion.
Rephrase the answer choices as STATEMENTS.
The correct rephrase will either STRENGTHEN OR WEAKEN the implied conclusion.

B, rephrased:
The newborns in both nurseries were equally healthy and happy at the start of the experiment.
Here, all of the newborns were equally healthy at the start of the experiment, strengthening the conclusion that the babies in nursery A had better outcomes because of the type of music played in nursery A.

The correct answer is B.