A scientific hypothesis must be testable and falsifiable because hypothesis is only a suggested explanation of a given problem and it is therefore, important to check its correctness by performing an experiment.
A hypothesis is proposal or a statement that proposes a possible explanation to an event or a phenomenon. A good hypothesis is a testable statement which may include a prediction. The basic requirement that a scientific hypothesis should have is that; it should be falsifiable and it must be testable. If a hypothesis does not have those two characteristics then it should be modified or discarded since it can not be rue.
