An internal auditor is testing the success of the IT support department in meeting the service levels guaranteed to small, medium, and large customers. The customer's size classification is based on its annual expenditures with the organization and the nature and extent of services it receives. Which of the following sampling techniques would be the most suitable to select customers for this test?
Stratified sampling is the most suitable technique for this situation because it involves dividing the population into distinct subgroups or strata (in this case, small, medium, and large customers) and then randomly selecting samples from each stratum. This method ensures that all customer size classifications are represented and allows for a better assessment of the IT support department's performance across different customer groups.
D is the answer