Dr. Longman wanted to know about the effect of light on work performance. She changed the lights for one group and left the lights the same for another. She was doing a(n): A. experiment. B. naturalistic observation. C. survey. D. correlational study.

Dr. Longman was conducting an:<br /><br />A. experiment.<br /><br />In an experiment, the researcher manipulates one or more variables (in this case, the lighting conditions) to observe the effect on another variable (work performance). This allows for the determination of cause-and-effect relationships.