Q15. An investigator is interested in the effects of noise on the ability of subjects to concentrate. She assigns subjects randomly to one of three Noise conditions: low noise, moderate noise, and loud noise. She administers a test of concentration while the noise is present. She predicts that there will be an overall effect of noise on the ability to concentrate. Theory A suggests that people in the low noise condition will have higher scores on concentration than subjects in the moderate noise condition, but that no difference in concentration will be observed between subjects in the moderate and loud noise groups. Theory B suggests that subjects in the moderate