In chemistry, as in any other science, there are two kinds of experiments. One involves qualitative observation, or perhaps semiquantitative measurement, and is performed to permit giving a yes-or-no answer to some question such as "does this compound contain an amino group?" or "does this substance exhibit significant bacteriostatic activity?" The other involves precise quantitative measurement and is performed so that some numerical value can be assigned to a quantity or physical parameter that characterizes the system being studied or the kind of behavior being observed.