3. It is suggested that a Poisson distribution with parameter \(\lambda\) can model the number of currants in a currant bun. A random bun is selected in order to test the hypotheses \(\mathrm { H } _ { 0 } : \lambda = 8\) against \(\mathrm { H } _ { 1 } : \lambda \neq 8\), using a \(10 \%\) level of significance.
- Find the critical region for this test, such that the probability in each tail is as close as possible to \(5 \%\).
- Given that \(\lambda = 10\), find
- the probability of a type II error,
- the power of the test.
(4)