In the grass seed example, the problem states that the manager wants to "know if the bags are being filled properly" which means whether the bags are being overfilled or underfilled. It always helps to start with the alternate hypothesis, which is what you are trying to prove. Since you're trying to prove that the bags are being over or underfilled, the alternate hypothesis would be H: mu not equal to 50 Where the "does not equal" sign signifies this is a two tailed test. Thus, the null would be: Ho: mu equals 50 The null and alternate hypotheses have to be mutually exclusive and collectively exhaustive. That means the cover all the scenarios, less than, greater than, and equal to. If the problem were to state the manager wants to determine if the bags are being overfilled, can anyone say what the null and alternate would be