Researchers are investigating the effect of pHpH level in water on the breeding habits of the moon jellyfish. As part of a laboratory experiment, they will randomly assign one of three treatments, low pHpH, medium pHpH, or high pHpH, to the water in the tanks that hold the jellyfish.
Which of the following is the best reason for the random assignment of a treatment level to an experimental unit?
Randomization tends to minimize the effects of uncontrolled variables, such as water temperature, so that such factors are not confounded with the treatment effects.