Question 4 Murtoch ERP is a Payroll Company that handles payroll services for many affluent customers. The process of distributing payroll invoices is not without error and from the invoices sent out per month there is an average of 3 in 10 being returned with an error. Using this information answer the questions (i-iv).

i) If 20 invoices were selected at random, what is the probability of exactly 5 invoices being returned?[3] i) If 12 invoices were selected at random, what is the probability that at least 3 were returned with an error? [4] ii) If 8 invoices were selected at random what is the probability that at most 6 invoices would not have an error? [3] iii) If 40 invoices were selected what is the average number of invoices that would have an error? [2] iv) Discuss with an example the type 1 and type 2 errors that can occur in hypothesis testing [4] v) Differentiate between a discrete and continuous distribution. [2] vi) With the aid of an example describe a point estimate and interval estimate. 2