students to participate in a sleep experiment. Each student had a sleep tracker watch to wear at home for the two-week study. Each morning they

students to participate in a sleep experiment. Each student had a sleep tracker watch to wear at home for the two-week study. Each morning they were asked to open the sleep tracker app to view their sleep quality data on their mobile phones. The students were unaware that the sleep data they could see on their phones had been manipulated by the researcher. Over the two weeks of the study, each student saw that he or she had had poor sleep quality for seven random nights of the experiment and good sleep quality for the remaining nights. Every morning, after viewing the sleep data, each student completed a questionnaire about the previous night’s sleep. One of the questions asked the students to rate how well rested they felt, on a scale from 1-10, after the previous night’s sleep. Apart from this, students were asked to continue their normal everyday activities. Which of the following best describes the experimental method used in this study? S [1 mark] A Field experiment B Laboratory experiment C Natural experiment D Quasi-experiment