The Chemistry Book

A scientific hypothesis is a proposed explanation of an observation that is tentative (temporary) and testable. Some students are introduced to the definition of a hypothesis using the phrase "educated guess." Be careful of this simplicity; some individuals focus on the _guess_ and do not realize the guess is not to a willy-nilly idea but a thoughtful explanation based on prior-knowledge or research done by others.

The statement may be written in an "if... then...because..." format. In this type of statement, the researcher considers the independent and dependent variables.

• An 'independent variable' is the variable in an experiment that varies or the researcher manipulates.
• The 'dependent variable' is the variable that as a direct effect of the independent variable is the response that is being measured.

Scientists usually consider two hypotheses during an experiment. The hypothesis that is the prediction is called the alternative hypothesis, and the hypothesis that "describes the remaining possible outcomes the null hypothesis." ^[1] As you advance in your study of science, you will recognize that the null hypothesis in some research is a statistical quantity - useful for determining if the result is due to chance or not.

Further Reading

• http://udel.edu/~mcdonald/stathyptesting.html

See Also

• Theory
• Laws

References