19. The auditor wishes to sample the perpetual inventory records to develop an estimate of the monetary amount of misstatement, if any, in the account balance. The account balance is made up of a large number of small-value items and a small number of large-value items. The auditor has decided to audit all items over US $50,000 plus a random selection of others. This audit decision is made because the auditor expects to find a large amount of errors in the perpetual inventory records but is not sure that it will be enough to justify taking a complete physical inventory. The auditor expects the errors to vary directly with the value recorded in the perpetual records. The most efficient sampling procedure to accomplish the auditor's objectives is
A. Monetary-unit sampling.
B. Ratio estimation.
C. Attribute sampling.
D. Stratified mean-per-unit sampling.
ANSWER (B) is correct.
REQUIRED: The most efficient sampling procedure.
DISCUSSION: Ratio estimation estimates the population misstatement by multiplying the recorded amount of the population by the ratio of the total audit amount of the sample to its total recorded amount. It is reliable and efficient when small errors predominate and are not skewed. Thus, ratio estimation should be used in this situation because the auditor is not sampling the very large items and the errors are not skewed (they vary directly with the size of the recorded values).
Answer (A) is incorrect. Monetary-unit (probability-proportional-to-size) sampling becomes less accurate when many errors are expected.
Answer (C) is incorrect. Attribute sampling is not used to estimate a monetary amount.
Answer (D) is incorrect. Mean-per-unit (MPU) variables sampling averages audit values in the sample and multiplies by the number of items in the population to estimate the population value. When many errors are expected, MPU and stratified MPU are not as efficient as ratio estimation.