A textile manufacturer produces fabric where flaws occur randomly at a constant rate of 1 flaw every 15 metres. After a maintenance check of the looms, a random sample of 60 metres of fabric is inspected to see if the rate of flaws has changed.
Stating your hypotheses clearly and using a 10% level of significance, find the critical region for this test. You should choose your critical region so that the probability of rejection is less than 0.05 in each tail.
State the actual significance level of this test.
A consultant suggests a new weaving adjustment that they claim will reduce the rate of flaws. The manufacturer tests this by inspecting a random sample of 300 metres of fabric produced with the adjustment and finds 13 flaws.
Using a suitable approximation, test the consultant's claim at a 5% level of significance. State your hypotheses clearly.
308 exam-style questions on WJEC A Level Maths 4.3 Statistical hypothesis testing (A-level only), covering 4.3.1 Statistical hypothesis testing (A-level only) and 4.3.2 Statistical hypothesis testing (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.