Katie is conducting a within subjects design. Her independent variable has 2 levels that must occur 1 week apart. In the first session during the first week, Katie has 120 participants. However, a week later when the second session occurs, Katie only has 85 participants show up for the study. What disadvantage to within subject designs is Katie encountering

attrition

Explanation:

Attrition in research is said to be when individuals or  participants abort or stop his/her involvement  during  a research study. It almost always happens to some extent. participants leaves a research study due to certain factors  or circumstances usually beyond their control. when participant of a research leaves or remove his/herself from an experiment, it sometimes can make  the study to be aborted, findings experience difficulties and slowing down of research study.