A quality analyst wants to construct a sample mean chart for controlling a packaging process. He knows from past experience that whenever this process is under control, package weight is normally distributed with a mean of 20 ounces and a standard deviation of two ounces. Each day last week, he randomly selected four packages and weighed each: What is the standard deviation of the sampling distribution of sample means for whenever this process is under control? 2 ounces 0.1 ounces 1 ounce 0.5 ounces 0.4 ounces.