Does each situation describe a survey, an experiment, or an observational study?
Select Survey, Experiment, or Observational Study for each situation.
Survey,Experiment,Observational Study
Patients who visit a clinic for the first time are asked to answer 15 questions about their health history.
A researcher randomly chooses 20 patients who come to the clinic with the flu and gives them an experimental drug. A randomly chosen group of 20 patients who come in with the flu receive a placebo.
A doctor at the clinic asks patients who come in with a headache how many hours of sleep they get on a typical night.
