To compare the hearing capacities of 5 of his friends, Ravi designs a simple experiment. He places a CD player at the end of a long hall containing a CD with 5 well-known songs. One by one each person hears the same 5 songs he plays softly but at a pre-determined volume.

Each person starts at a distance of 1 metre from the player and moves away from it. The distance at which a person says that he cannot hear the song any more, is noted. Others are not in the room when 1 person is hearing the songs.
Which of these steps may increase the reliability of the results obtained?

A)having each person listen to just 1 song instead of 5
B)allowing all people to stay in the room for the entire experiment
C)having each person start from far and walk towards the C
D )player Dvarying the volume for the different songs being played

A) having each person listen to just 1 song instead of 5.

Explanation:

Ravi could accurately use the outcome to compare the hearing capacities of his friends by this experiment if appropriate precautions are observed.

Playing 5 well known songs simultaneously could result to the interference of sounds when each participant moves away from the player. Which could naturally cause the variation in volume of the songs played with respect to the increasing distance.

Therefore, the reliability of the result from this experiment can be increased if each person listen to just 1 song instead of 5 at a predetermined volume. Each participant would be able to focus on hearing a song during the experiment.

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