An audit is an independent, systematic examination of financial statements, typically performed by external auditors to provide assurance to stakeholders that the financial information is accurate and free from material misstatements. It is often required by law or regulation and focuses on expressing an opinion on whether the financial statements present a true and fair view. On the other hand, an internal audit is conducted by professionals within the organization. It is an ongoing process that evaluates the effectiveness of internal controls, risk management, and operational efficiency to support management in achieving organizational goals.

Both types of audits rely on audit sampling, which involves selecting and testing a representative portion of data rather than examining the entire population. This approach saves time and resources while still providing sufficient evidence for decision-making.

For example, in an external audit of a retail company, the auditor may select 100 out of 10,000 sales transactions to test revenue accuracy and compliance with accounting standards. Meanwhile, an internal auditor in the same company might sample warehouse inventory records quarterly to detect discrepancies and assess stock management controls. Though their goals differ, both use sampling to reach reliable and efficient conclusions in their audits.