Answer:
hypothesis
Step-by-step explanation:
Hypothesis of an experiment is a testable explanation or prediction of the outcome of an experiment, which is subject to testing via experimentation. The hypothesis, which aims at predicting a solution to a problem, must be testable to either be proven or disproven.
In this case, Yuri predicts that " the more practice tests one takes, the better one will do on the graded exams." This prediction gives an expected outcome, however, it must be tested by conducting an experiment. This prediction made by Yuri is called HYPOTHESIS.