Identify the correctly formulated null hypothesis:


A factory has a machine that dispenses 80 milliliters of fluid in a bottle. An employee believes the average amount of fluid is not 80 milliliters. Using 40 samples, he measures the average amount dispensed by the machine to be 78 milliliters with a standard deviation of 2. 5.


a

The machine dispenses 80 ml of fluid.

b

Ha: mu=80

c

H0: mu=80

d

The machine does not dispenses 80 ml of fluid