試験IIA-CIA-Part1 トピック9 問題36 スレッド

During an internal audit, an organization's processing department is found to have incidences of both duplicate invoices and notices from customers that purchased goods were not received. The department under review insists that some of these reports are false and that others were isolated oversights due to understaffing.
Which of the following tests would best help the internal auditor detect fraudulent activity?