Question 3 This question contains 2 parts [5 + 2] = 7 Marks 3.1 A random sample of 20 department stores of Maximus Pty Ltd was selected as part of a study on the average advertising expenses, and the expense amounts were recorded for each individual store in the sample. The sample average advertising expense was found to be = 65.9 ($000). a. Assuming that the advertising expenses is normally distributed with a sample standard deviation of 8.5 ($000), calculate a 95% confidence interval for the mean advertising expenses. (3 Marks) 1 A B I == E % $$ b. In a single sentence, provide an interpretation of your findings in the previous part. (2 Marks). A B I E % $3 M 3.2 With reference to question 3.1, if the same analysis was to be conducted in the future, what would the required sample size be, if they wish to have a margin of error at most 2 with a standard deviation of 8, to maintain a 95% confidence level? (2 Marks) J A B I E % S$