In: Economics
A machine in a Dairy of a milk supplier is set to fill milk in
one-litre pouches. The amount of
milk per pouches is normally distributed with a standard deviation
of 25 ml. Recently the
engineering department of the company has reset the machine aiming
to reduce the variability.
After resetting, a sample of 12 pouches is taken and the standard
deviation has been found to be
20 ml. Do you think this evidence is sufficient to conclude that
the engineering department has
been successful? Test the hypothesis using α=0.05. Write all the
assumptions for the test.