5. [4 marks] An Internet server conducted a study on 225 of its customers and found that the average amount spent online was 12.5 hours per week with a standard deviation of 5.4 hours. Construct a 95% confidence interval for the average online time for all users of this particular Internet server. 6. [4 marks] A salesperson has found that the probability of making a sale on a particular product manufactured by him or her company is .05. If the salesperson contacts 140 potential customers, what is the probability he or she will sell at least 2 of these products? Use and justify Poisson approximation to Binomial. 7. [ 4 marks] A firm with many traveling salespersons decides to chock the salesper- sons travel expenses to see if they are correctly reported. An auditor for the firm selects 200 expense reports at random to audit. What is the probability that more than 40 of these 200 sampled reports will be incorrect when, in fact, only 10% of the firm's reports are improperly documented. Use and justify normal approximation to binomial