Question 3 25 marks You should be able to answer this question after working through Unit B3. i. ii. The MINITAB worksheet LoanApplicant . mtw contains measurements of the 30 loan applicants. You may assume that the income and age of the applicants may be adequately modelled by a normal distribution. Use the data to calculate an exact 95% condence interval for the income and age. State which method you use to calculate the condence interval, explain briey Why this method is appropriate and provide the interpretation of the results. [10] A quality inspector is labeling the products at production line with labels either "non- conforming" or "conforming." In order to estimate the proportion of non-conforming products, a random sample of 100 products are selected om the production line and 10 are found to be non-conforming products. To monitor the quality of the production line, another set of 100 samples is taken and observed that only 6 non-conforming products are found. [10+05=15] (a) Give a 95% condence interval on P1 P2 , where P1 is the population proportion non conforming before improvement, and P2 is the proportion non-conforming after improvement. (b) Is there information in the condence interval found in (a) that would suggest that P1 > P2? Explain