A new water fountain designed for cups/bottles has a program that is designed to stop after it has dispensed 12 oz of water. However, several of the staff who use the
fountain have noticed that their cups are slightly lower than usual. As a test, they
obtain a random sample of 5 cups of water, and set up the null hypothesis that the
mean oz of water = 12, against the alternative that it is in fact less. If the machine
operates with a known standard deviation of 0.9 oz, which of the following best
describes a test statistics that would lead the employees to conclude their machine is
not working properly?