Final answer:
The hypothesis in the statement is 'Melissa practices the flute,' which is the condition that leads to the result of playing well.
Step-by-step explanation:
The hypothesis in the statement 'If Melissa practices the flute, then she plays well' is 'Melissa practices the flute.' In a conditional statement of the form 'If P, then Q,' the hypothesis is the part that follows the 'if.' Therefore, the hypothesis here is the suggestion that practicing is correlated with playing well.