CISA Information System Auditing Process Practice Question
Which of the following best describes the primary advantage of using statistical sampling over non-statistical sampling in an IS audit?
⚠ Common exam trap
The trap is equating 'statistical' with 'better at finding fraud' or 'more thorough' — the exam wants you to recognize that the unique benefit is quantifiable sampling risk and projection, not detection capability or coverage.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
It provides a basis for quantifying sampling risk and projecting results to the population.
Statistical sampling uses probability theory to select samples, which allows the auditor to quantify sampling risk and mathematically project sample results to the full population. This is its defining advantage over non-statistical (judgmental) sampling, which relies on auditor judgment and cannot support statistically valid projections. The other options describe goals that neither method guarantees.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
It is more effective for detecting fraud than non-statistical sampling.
Why it's wrong here
Statistical sampling provides measurable precision and confidence intervals, not fraud detection; sampling tests controls, and fraud typically requires targeted, judgemental procedures. It is tempting because larger samples feel thorough, but detection of intentional misstatement is not its purpose.
- ✗
It ensures that all items in the population are tested.
Why it's wrong here
Statistical sampling tests a subset drawn from the population, so items outside the sample remain untested; it quantifies sampling risk rather than eliminating it. It is tempting because sampling implies coverage, but 100% testing is a separate, non-sampling approach.
- ✓
It provides a basis for quantifying sampling risk and projecting results to the population.
Why this is correct
Statistical sampling applies probability theory, allowing the auditor to quantify sampling risk and extrapolate sample results to the full population within defined confidence limits. Non-statistical sampling relies on judgement, providing no mathematically defensible basis for such projection.
- ✗
It requires less auditor judgment and is easier to apply.
Why it's wrong here
Statistical sampling demands more auditor judgement in defining the population, parameters and evaluation, not less; its advantage is quantifiable sampling risk. It is tempting because formulas appear mechanical, but judgement is concentrated at design stage rather than eliminated.
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official ISACA exam blueprint
This CISA practice question is part of Courseiva's free ISACA certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the CISA exam.