CustomersA firm conducts ladder interviews with randomly selected customers from its stores in order to understand customer perceptions of its brand. Basic statistics such as gender and age are compared to the firm's customer database to ensure samples are representative. For example, if 20% of total customers are over age 60, the sample can not be considered representative if nobody over 60 was interviewed.
ProductsA bicycle helmet manufacturer performs basic quality control tests on all units. A more indepth test is run on 1 out of 20,000 units selected at random by an algorithm. The indepth test confirms that products meet safety and reliability standards. This results in the destruction of the product and is designed to detect problems with materials, parts or assembly.
ServicesA customer service manager listens to randomly selected calls to evaluate customer service levels. The firm finds that listening to 1 out of 200 calls is sufficient to identify issues and ideas for improvement. Customers are warned that calls may be monitored for the purposes of quality improvement.
Air QualityA city sets up air quality sampling stations at various points geographically distributed throughout the city as representative samples. Factors such as elevation and proximity to highways is considered in selecting the sites. The sampling stations are used to measure air quality on an ongoing basis to track the success of pollution reduction strategies and to issue health alerts to the public.
|Overview: Representative Sample|
A subset that accurately reflects a set for the purposes of analysis.