The production line that packages bags of almonds at a snack food manufacturer will be considered operating properly if the average weight of the bags of almonds is 2.3 ounces with a standard deviation of 0.09 ounces. A random sample of 14 boxes showed an average weight of 1.54 ounces.

What additional assumption is needed before we can perform a test to determine whether the production line is operating properly?

a. The sample standard devotion needs to be known.

b. The population mean needs to be known.

c. The population standard deviation needs to be known.

d. The population distribution of the weight has to be normal.