Final answer:
The sentence should be completed as: 'The less critical the factor, the broader the zone of tolerance is likely to be.' This concept applies to the range customers are willing to accept variations in service performance, which differs based on the importance of the service attribute.
Step-by-step explanation:
Customers' tolerance zones vary for different service attributes or dimensions. The less critical the factor, the broader the zone of tolerance is likely to be. In service management, the 'zone of tolerance' refers to the range within which customers are willing to accept variations in service performance. For instance, in a fast-food restaurant, the speed of service is a critical factor, and the tolerance zone for waiting time is narrow. In contrast, for a luxury dining experience, customers may have a broader tolerance for waiting because they expect a longer, more leisurely meal. Consequently, businesses must understand these tolerance levels to ensure customer satisfaction and service quality.