Answer:
Ceiling
Explanation:
A ceiling effect is being observed when the independent variable no longer have any effect on a dependent variable. In other words, the point above which a variance is no longer measurable in an independent variable.
In the context, Racheal is considered as an independent variable who has an interest in math skills. And both the groups are depended variable who are solving maths problems. According to Rachel, the students can answer only 2 percent of the problems which is due to the ceiling effect.