Evaluating Operational Definitions Heath Participated in a Study of the Effect

Multiple Choice

Evaluating Operational Definitions Heath participated in a study of the effect of meditation on blood pressure.Since he had never used a self-inflating cuff, he was afraid that the cuff would keep inflating and cut off blood to his arm.This fear caused his blood pressure to rise when he was measured during the pretest phase of the experiment.The experimenter also measured Heath's blood pressure after meditation training during the posttest phase.Since he was now used to the self-inflating cuff, his blood pressure was lower due to lack of panic.Based on Heath's experience, a ____ threat may have confounded this experiment.

A) history
B) maturation
C) selection
D) testing