(a) A toy manufacturer is concerned that Machine A is producing a higher pro portion of faulty toys than Machine B. To i
Posted: Wed May 11, 2022 9:12 am
(a) A toy manufacturer is concerned that Machine A is producing a higher pro portion of faulty toys than Machine B. To investigate this, the company have taken a random sample of 100 toys produced from each machine. It is found that 15 toys from Machine A and 8 toys from Machine B are faulty. Test, at a 5% significance level, the hypothesis that Machine A is producing a higher proportion of faulty toys. Hint: Test the difference between the proportions of faulty toys that are produced by Machine A and Machine B. A one sided test is required. (b) An alternative way of investigating whether Machine A is working correctly is to use a Shewart control chart. Draw the structure of a Shewart control chart based on the number of defectives in a sample of size n and explain briefly how the chart is used, giving the equations for calculating the lines within the chart. You may assume n is large and the target population of defectives p is known.