How would you audit the automobile revenues (say $100 billion)
of General Motors?
Let’s say that each car and truck has an invoice on the window and
in GM's computer system, and that 8 million cars and trucks were
sold.
Then, how many invoices out of 8 million should you want to
examine (audit) in order to verify the $100 billion of
revenues in the financial statements? So, you, as the auditor,
would feel “comfortable” to sign the auditor’s report...