Final answer:
An employee watching the salad bar usage is conducting an observational study to measure characteristics or behaviors without manipulating variables.
Step-by-step explanation:
Having an employee watch the salad bar usage qualifies as a observational study. This type of research design involves the researcher or observer measuring characteristics or behaviors in a sample without attempting to manipulate or control the variables of interest. In this case, the employee would be watching how people use the salad bar to gather data on consumption patterns, preferences, or other variables of interest. The honesty of the data that is collected in a realistic setting is a significant benefit of naturalistic observation studies like this.