Answer:
Observational study
Step-by-step explanation:
An observational study is one in which the researcher draws inferences from a sample to a population, but where the independent variable is not under the control of the researcher. This can occur for various reasons, but most often, it is the result of logistics or ethical concerns. In this example, the researcher cannot manipulate the way people operate. He cannot divide them into groups nor can he have a control group. However, he can overcome these problems in logistics by simply observing their behaviour.