Final answer:
A Within-Subjects design can increase the statistical power of an experiment by controlling for participant variability and reducing error variance.
Step-by-step explanation:
A Within-Subjects design is an experimental design where the same participants are exposed to different levels of the independent variable. This type of design can increase the statistical power of an experiment. By using the same participants, any variability between participants is controlled for, thereby reducing error variance and increasing the ability to detect a true effect. This leads to a higher statistical power, which means a greater chance of detecting a significant difference between groups if one exists.