Phillipe, a researcher, examined the effect of lighting on learning. Randomly selected participants were asked to learn the same chapter using either a 100-watt or a 125-watt bulb. He found no difference between the learning capacities of the two groups. The nonsignificant results may have occurred because of:.

insufficient strength of the manipulation

Explanation:

The non-significant results may have occurred because of insufficient strength of the manipulation. Since the variable being tested in this scenario had a very slight difference it caused insignificant results. The variable in the study (light bulb) needs to be drastically different in order for it to have an effect on the subjects and provide results that differ. The 100-watt and 125-light bulb provide almost the same luminosity levels.