Either hypothesis—the null hypothesis or the alternative hypothesis—may represent the original claim!
Regardless of whether you're making a statement about the mean or a proportion, regardless of which hypothesis is the claim, remember that the null hypothesis must contain a symbol of equality and the alternative hypothesis must complement it. Here are some examples of possible hypothesis pairs:
Note: For an example of making a prediction or forecast using your pre-calculated linear regression equation, skip to 7:25 and watch until 8:15. Also note that the presenter arbitrarily rounds the values of a and b. Be sure to round as indicated on your homework, quizzes, or tests.