It is known that 17% of the cars serviced at a garage need a new air filter. The manager believes that this proportion has increased since a change of supplier.
A random sample of 60 cars serviced since the change is taken, and 16 of them need a new air filter.
Stating your hypotheses clearly, test the manager's belief at the 2.5% significance level.
State, with a reason, the conclusion you would have reached at the 5% significance level.