4. A company produces sweets of varying colours. The company claims that the proportion of blue sweets is \(13.6 \%\). A consumer believes that the true proportion is less than this. In order to test this belief, the consumer collects a random sample of 80 sweets.
- State suitable hypotheses for the test.
- Determine the critical region if the test is to be carried out at a significance level as close as possible to, but not exceeding, \(5 \%\).
- Given that there are 6 blue sweets in the sample of 80, complete the significance test.
- Suppose the proportion of blue sweets claimed by the company is correct. The consumer conducts the sampling and testing process on a further 20 occasions, using the sample size of 80 each time. What is the expected number of these occasions on which the consumer would reach the incorrect conclusion?
- Now suppose that the proportion of blue sweets is \(7 \%\). Find the probability of a Type II error. Interpret your answer in context.