12. The size of a given sample is jointly a result of characteristics of the population of interest and decisions made by the internal auditor. Everything else being equal, sample size will
A. Increase if the internal auditor decides to accept more risk of incorrectly concluding that controls are effective when they are in fact ineffective.
B. Double if the internal auditor finds that the variance of the population is twice as large as was indicated in the pilot sample.
C. Decrease if the internal auditor increases the tolerable rate of deviation.
D. Increase as sampling risk increases.
ANSWER (C) is correct.
REQUIRED: The true statement about the effect on the sample size resulting from a change in a relevant variable.
DISCUSSION: In an attribute test, the tolerable deviation rate is inversely related to sample size. If it is increased, sample size will decrease.
Answer (A) is incorrect. An increase in allowable risk decreases sample size.
Answer (B) is incorrect. Doubling the variability of the population will cause the sample size to more than double.
Answer (D) is incorrect. Sampling risk increases as the sample size decreases.