Question

A tire manufacturing plant produces 15.2 tires per hour. This yield has an established
variance of 2.5 ( =1.58 tires/hour). New machines are recommended, but will be expensive
to install. Before deciding to implement the change, 12 new machines are tested. They
produce 16.8 tire per hour. Is it worth buying the new machines? Before testing, verify that
the data comes from a normal distribution (assumption of the test)

a) State the hypothesis
b) Find the critical region
c) Conclude the test .

Answer 1