The queuing theory addresses problems involved in waiting. Typical examples of queuing in business include the lines of people waiting for service at banks and supermarkets and the queues caused by PRODUCTION shutdowns, public transport delays, and slow computer response times. In each of these situations, COSTS and benefits must be weighed. Shorter queues increase customer satisfaction but also are more costly to businesses.

Questionnaires are used to collect data in MARKET RESEARCH. Whether used in MAIL SURVEYS and INTERNET SURVEYS or TELEPHONE SURVEYS and PERSONAL-INTERVIEW SURVEYS, questionnaire design is critical to successfully obtaining the information needed to achieve the research objectives.

Quality control is a system for ensuring the maintenance of proper standards in manufactured goods using periodic random inspection of the PRODUCTs. It is also used for optimizing PRODUCTION.