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.

Patients who visit a clinic for the first time are asked to answer 15 questions about their health history.

Survey

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.

Experiment

A doctor at the clinic asks patients who come in with a headache how many hours of sleep they get on a typical night.

Observational Study

A survey : survey sampling is the process of selecting a sample of elements from a target population to conduct any survey.

An experiment : an experiment is a procedure that can be infinitely repeated and can have many possible outcomes.

An observational study - observational studies are done to understand cause and effect relationships.

Survey  - Patients who visit a clinic for the first time are asked to answer 15 questions about their health history.  

Experiment - 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.

Observational Study - A doctor at the clinic asks patients who come in with a headache how many hours of sleep they get on a typical night.