What is the most important difference between an experiment and an observational study?

The most important difference is that in experiment the objects on which the procedure is carried out on or with can be determined/controlled

while in observational study you can't determine that because you only observe a result been produced by an experiment

Step-by-step explanation:

An experiment is a procedure undertaken by a person or a group of persons to make a discovery, refute or validate a hypothesis, or to prove an existing fact on ground already. experiments are carried out by manipulating a factor involved in the hypothesis, discovery or known fact to get an outcome.

while an observational study is the observation of the effect of a test been carried out like environmental test, diagnostics test and even a kind of treatment of any kind without controlling the subjects who feel the effect or control how they are exposed to it.

Answer and Explanation; The most important difference between an experiment and an observational study is the fact that;. In an observational study the researcher has no control over the variables while an experiment involves application of treatments to a group and recording the effects. In an observational study researchers observe subjects and measure variables of interest without assigning treatments to the subjects. The treatment that each subject receives is determined beyond the control of the investigator. In an experiment investigators apply treatments to experimental units (people, animals, plots of land, etc.) and then proceed to observe the effect of the treatments on the experimental units