You are completing the audit of Centre Pty Ltd. You read a note in the file from your assistant, Susan Jones, which states,

In performing a substantive test of transactions for purchases, I selected a sample of purchase orders and inspected them to determine if they had been authorised by the Purchasing Manager. The sample deviation rate was 4%, which was less than the tolerable deviation rate stated in the audit program, so I concluded that the test for the occurrence assertion for purchases was satisfied.

REQUIRED: Is Susan justified in forming the conclusion that she did? Give the reason for your answer.