15-33 ( Objectives 15-5 , 15-7 ) In performing tests of controls and substantive tests of transactions of sales for the Oakland Hardware Company, Ben Frentz, CPA, is concerned with the internal verification of pricing, extensions, and footings of sales invoices and the accuracy of the calculations. In testing sales using audit sampling, a separate attribute is used for the test of control (the existence of internal verification) and the substantive test of transactions (the accuracy of calculation). Because internal controls are considered good, Frentz uses a 10% ARACR, a zero EPER, and a 5% TER for both attributes; therefore, the initial sample size is 45 items, which Ben rounded up to 50. In conducting the tests, the auditor finds three sample items for which there was no indication of internal verification on the sales invoice, but no sales invoices tested in the sample had a financial misstatement. You may complete the following requirements using either a nonstatistical sampling or an attributes sampling approach. Required a. Estimate or determine the CUER for both the attributes, assuming a population of 5,000 sales invoices