Jarr, with the accounting firm of Mason & Jarr, audited the Repairs and Maintenance account of Kerr Corporation by vouching all entries of more than $5,000 (totaling $278,000)to supporting documents. She compared the sum of all remaining entries ($75,000, a material amount) in relation to the prior-year total of $56,000 and decided the amounts were reasonable and did not perform any additional procedures with respect to these entries.

The two partners of Mason & Jarr are worried about properly applying professional standards regarding audit sampling. They have asked your advice. What would you advise the partners in this regard?