State whether the following would be an observational study or an experiment: test the effects of breakfast on grades I ask my students if they ate breakfast a then compare the breakfast eaters grades to the non-breakfast eaters.
This is an example of:
Observational study
Experiment
The correct answer and explanation is:
This is an example of an observational study.
In an observational study, the researcher observes or measures outcomes without manipulating the independent variable. Here, the researcher is simply asking students whether they ate breakfast and then comparing the grades between the two groups (breakfast eaters vs. non-breakfast eaters). Since the researcher is not controlling who eats breakfast or when, but only observing existing behaviors, it qualifies as an observational study.
If this were an experiment, the researcher would have actively controlled who ate breakfast and who did not, possibly assigning breakfast as a condition for some students and withholding it from others. In experimental studies, researchers apply some form of intervention or manipulation to test its effect on an outcome. However, in this case, no such intervention takes place.
The key difference between an observational study and an experiment is the level of control over variables. In observational studies, variables are observed in their natural setting without interference, which limits the ability to infer causality. For example, in this case, while a correlation between breakfast and grades could be observed, other factors (like study habits, sleep, or family background) could also be influencing the results. An experimental approach would allow for a more controlled examination of the relationship by isolating breakfast as the only changing factor.
Overall, since the researcher is observing and comparing, without manipulating the conditions of breakfast consumption, it remains an observational study.