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Statistical Sampling for Internal Auditors

Course Description

Print-friendly Course Description and Outline

​Knowing which method of sampling is most appropriate for different situations, estimating the sample size needed to provide the desired confidence level, and assigning sample size strategically to get the most information at the lowest cost are critical steps to executing a successful audit.

This course provides an opportunity for you to learn about the pitfalls you face in selecting the most appropriate sampling methods, calculating sample size, and creating an audit design that will provide the most information at the minimum cost. Topics covered include different methods of random sampling and non-random selection, adjusting for population size and resource constraints, how to combine results and extrapolate, and what to report.

This course is appropriate for auditors, managers, and executives working in both the public and private sectors.

Course Objectives

  • Summarize introductory terminology and methodology related to sampling.
  • Employ random sampling techniques.
  • Understand why haphazard sampling should not be used.
  • Identify the criteria for non-random selection techniques.
  • Apply the binomial equation formula to calculate sample size.
  • Employ methods for adjusting sample size.
  • Practice combining results, given a scenario.
  • Describe elements within the report.
  • Balance resources by tracking the various evidence collection methods and tests of controls in the audit program.
In-person classes are 2 day(s). For online courses, please click on the Details & Pricing link to review session times and dates.
Course Duration: 2 day(s)
CPEs Available: 16
Knowledge Level: Basic
Field of Study: Statistics


Advance Preparation: 


Delivery Method: eLearning (Group-Internet-Based); On-site Training (Group-Live); Seminar (Group-Live)

Introduction to Statistics

  • Defining Statistics
  • Statistical Techniques
    • Descriptive Statistics
    • Inferential Statistics
  • Population
  • Random Sample
  • Variables
  • Random Sample vs. Population Census
  • Sampling Method vs. Sample Size

Random Sampling

  • The Randomness Assumption
  • Types of Random Sampling
    • Simple Random Sampling
    • Stratified Random Sampling
    • Dollar Unit Sampling
    • Stop-or-Go Sampling
    • Haphazard Sampling

Non-Random Selection

  • Defining Non-Random Selection
  • Fraud Red Flags
  • How to Perform Non-Random Selection
  • The Credibility Obstacles
  • Case Study Using Non-Random Selection

Calculating Sample Size

  • Drivers of Sample Size
  • Binomial Equation
  • Confidence Level
  • Expected Error Rate
  • Precision
  • Pilot Studies

Adjustments to Sample Size

  • Population Size
  • Resource Constraints
  • Strength of Generalization
  • Bias and Ethics

Knowledge Check

  • Practical Exercises in Calculating Sample Size, Adjusting Sample Size, and Interpreting Results

Combining Results

  • Nomenclature
  • Combining Error Rates
  • Other Weighted Averages
  • Combining Non-Random Data
  • Generalization and Extrapolation
  • Statistical Tests


  • Mock Report
  • What to Include

Audit Program

  • Why Do an Audit Program?
  • Audit Program Example
  • Sortable Audit Program
  • Audit Program vs. Audit Sampling

​Most courses can be delivered through on-site training. You might be surprised that the organization leading the profession is just as committed to the delivery of affordable training.

Contact us by calling +1-407-937-1388 or send an e-mail to