The given statement is
If Lindsey studies for her test, then she will pass.
This statement is defining a relationship between a hypothesis and a conclusion. Remember that a hypothesis is a supposition, it's the "if" about the statement. In this case, the hypothesis would be "Lindsey studies for her test", and the conclusion would be "she will pass".
Therefore, the answer is
"Lindsey studies for her test" is the hypothesis.