A package-filling device is set to fill jars of jelly with a mean weight of 16 ounces of jelly per jar. The standard deviation of the amount actually put into the jars is .5 ounces. A random sample of 40 filled jars is weighed, yielding a mean weight of 16.2 ounces. Test at the .01 significance level to see if the jars are being properly filled.

Would the sample mean be 16 oz and the null hypothesis be 16.2?

Thanks in advance for your help.