Answer: observational study
Explanation:
Observational study : A study in which an observer analyse one or more characteristics of a population (depends on the objective of the study) by just observing the individuals in a sample of the population, but he / she never influence the variables of interest.
Design experiment : In this experimenter design an experiment with a series of tests to check the change in the dependent variable. Here , the experimenter influences the variables of interest.
Given : A poll is conducted in which 574 high school students are asked about how often they listened to music during the past week.
here , the poll is just observing the interest of students instead of influencing them.
Hence, the study depicts an observational study.