Final answer:
A controlled experiment is a type of scientific investigation performed under controlled conditions to manipulate variables and observe effects, typically conducted in a laboratory setting.
Step-by-step explanation:
A carefully designed test done under controlled conditions is known as a controlled experiment. An experiment is a type of scientific investigation that involves manipulating one or more variables (independent variables) to observe the effect on another variable (dependent variable). This process helps in testing a hypothesis and is conducted in a controlled environment to isolate the effects of the manipulation and limit extraneous factors.
This often involves the use of control and experimental groups where the latter undergoes the experimental manipulation while the former does not, thus serving as a benchmark. Repetition and a sufficient sample size help improve the validity of the experiment and enable researchers to generalize their findings to a larger population.