Design leads to hypothesis-driven research.
The application of the scientific method is limited to independently observable, measurable events that can be reproduced. The scientific method is also applicable to random events that have statistical distributions. In atomic chemistry, for example, it is impossible to predict when one specific atom will decay and emit radiation, but it is possible to devise theories and formulas to predict when half of the atoms of a large sample will decay. Irreproducible results cannot be studied by the scientific method. There was one day when many car owners reported that the alarm systems of their cars were set off at about the same time without any apparent cause. Automotive engineers were not able to discover the reason because the problem could not be reproduced. They hypothesized that it could have been radio interference from a passing airplane, but they could not prove it one way or another. Mental conceptual experiences cannot be studied by the scientific method either. At this time there is no instrumentation that enables someone to monitor what anybody else conceives in their mind, although it is possible to determine which part of the brain is active during any given task. It is not possible to define experiments to determine objectively which works of art are "great", or whether Picasso was better than Matisse. So-called miracles are also beyond the scientific method. A person has tumors and faces certain death, and then, the tumors start shrinking and the person becomes healthy. What brought about the remission? A change in diet? A change in mental attitude? It is impossible to go back in time to monitor all variables that could have caused the cure, and it would be unethical to plant new tumors into the person to try to reproduce the results for a more careful study.
Formulation of an hypothesis to explain the phenomena.

Identifying variables is necessary before you can make a hypothesis.
Hypotheses, Models, Theories and LawsIn physics and other science disciplines, the words "hypothesis,""model," "theory" and "law" have different connotations in relation to thestage of acceptance or knowledge about a group of phenomena.An hypothesis is a limited statement regarding cause and effect inspecific situations; it also refers to our state of knowledge beforeexperimental work has been performed and perhaps even before new phenomena havebeen predicted.
There is usually one hypothesis for each question you have.
My hypothesisis that many cases of cyclical overheating (temp gauge going up and downrepeatedly while driving at fairly steady speed and incline) are causedby combustion gasses escaping the cylinders into the coolant through aflaw in the head gasket.
