Many Experiments Omit the Pretest Section of an Experiment Because

Many experiments omit the pretest section of an experiment because it risks influencing the effects of the experimental treatments. Which of the following reflect possible outcomes of using a pretest? (circle all that apply)

A) The pretest will sensitize participants to the treatment, artificially enhancing the treatment effect.
B) The pretest will sensitize participants to the treatment, artificially weakening the treatment effect.
C) The pretest will change participants' responses such that their responses on the pretest no longer reflect their opinions or attitudes at the time of the experimental treatments.
D) The pretest will determine whether treatment groups' pretest scores are similar at the outset of a study (before exposure to any treatments) .