Question 1 A survey of mortgage holders at the current time shows that 17% are in arrears with their mortgage repayments. Out of the 300 people surveyed, 48% report that they are currently able to manage, while some in the sample also report that although they are not in arrears, they fear for the future. Infer a 99% confidence interval for the proportion of all mortgage holders who are currently in arrears with their mortgage repayments.

Question 2 In a low-temperature performance test (CCA test) of 170 vehicle batteries, an average current reading of 160A is observed, with a standard deviation of 14A. Infer a 95% confidence interval for the current output of a battery selected at random.