DrMentor Is Conducting an Experiment Examining the Effects of Cell

Multiple Choice

Dr.Mentor is conducting an experiment examining the effects of cell phone conversations on reaction times while driving a car.Each participant,either conversing on a cell phone or not,manoeuvres a driving course on a simulator.This simulated drive is videotaped.The research assistant hired to do the coding of the video tapes does not believe cell phone use should be banned while driving a motor vehicle and tends to err in the coding of the reaction times in a way that favours this belief.This experimenter expectancy effect could be controlled by:

A) the double-blind procedure
B) counterbalancing
C) the placebo effect
D) improved external validity