Question

You are conducting an experiment to test the hypothesis that dairy cows will givemore milk if they listen to classical music while being milked. Your 20 experimentalcows listen to classical music during milking; you collect all their milk and measurehow much there is. Your 20 control cows should have all experimental conditionsidentical to the experimental cows exceptA they should listen to classical music at a louder volumeB. they should listen to classical music all the time, not just during milkingC. they should listen to a different type of music, like heavy metalD. they should not listen to any music

Answer 1

The 20 control coes should all have identical experimental conditions except that they should not listen to any music (option D) in order to be able to conclude that te effect on the incresment on milk production is due to the usic.

On the other hand, to control if the effect is caused by the type of music, it would be useful to test another control group of cows with a different tipe of music.