8 At a certain large school it was found that the proportion of students not wearing correct uniform was 0.15 . The school sent a letter to parents asking them to ensure that their children wear the correct uniform. The school now wishes to test whether the proportion not wearing correct uniform has been reduced.
- It is suggested that a random sample of the students in Grade 12 should be used for the test.
Give a reason why this would not be an appropriate sample.
A suitable sample of 50 students is selected and the number not wearing correct uniform is noted. This figure is used to carry out a test at the 5\% significance level. - State suitable null and alternative hypotheses.
- Use a binomial distribution to find the probability of a Type I error. You must justify your answer fully.
- In fact 4 students out of the 50 are not wearing correct uniform.
State the conclusion of the test, explaining your answer.
- State, with a reason, which of the errors, Type I or Type II, may have been made.
If you use the following lined page to complete the answer(s) to any question(s), the question number(s) must be clearly shown.