Answer:
b. hypothesis
Step-by-step explanation:
The statement, "We expect our study to show that students who sleep fewer than five hours the night be-fore the exam will perform more poorly than those who sleep more than five hours," would be considered a hypothesis.
A hypothesis is a proposed explanation for a phenomenon, a scientific guess, an idea or explanation that you test its validity through study and experimentation.
The statement is an example of a hypothesis that is subject to testing.