An IS auditor is analyzing a sample of accesses recorded on the system log of...

 Discovery sampling is an appropriate sampling method for an IS auditor who intends to launch an intensive investigation if one exception is found. Discovery sampling is a type of attribute sampling that determines the sample size based on an acceptable risk of not finding at least one occurrence of an attribute when a given rate of occurrence exists in a population. Discovery sampling can be used by an IS auditor who wants to detect fraud or errors that have a low probability but high impacton an audit objective. The other options are not appropriate sampling methods for this purpose, as they may involve judgmental sampling, variable sampling, or stratified sampling. References:

CISA Review Manual (Digital Version), Chapter 2, Section 2.31

CISA ReviewQuestions, Answers & Explanations Database, Question ID 230