The objective of most audits by independent auditors is to determine whether or not the financial statements of the auditor's client conform to generally accepted accounting principles. Suppose an auditor decided to test the operation of the accounts payable/cash disbursement system of Frederic's Clothing. A sample of checks written by the company is examined for propriety. For each canceled check there was a voucher jacket included with supporting documents. According to company policy, the number of checks without supporting documentation should be minimized. The auditor wants to estimate the proportion of checks without supporting documentation. What sample size would be needed to obtain a 90% confidence interval on the proportion of checks without documentation that has a margin of error of .02? Assume that an initial sample of size 150 was taken and that 12 were found not to have documentation.