I am learning that the 4 steps of hypothesis testing with the t statistic are: Step 1: State the hypotheses, and select an alpha level; Step 2: ________; Step 3: ________; and Step 4: ________.

I understand that the null hypothesis (H0) states: = 15 (Mu is equal to 15), which indicates: (There is no change.) and the alternative hypothesis (H1) states: ________, which indicates: ________.