A null hypothesis is a statistical hypothesis that is tested for possible rejection under the assumption that it is true (usually that
observations are the result of chance). The concept was introduced by R. A. Fisher.
The hypothesis contrary to the null hypothesis, usually that the observations are the result of a real effect, is known as the alternative
hypothesis.
Gonick, L. and Smith, W. The Cartoon Guide to Statistics. New York: Harper Perennial, p. 140, 1993.Kenney,
J. F. and Keeping, E. S. Mathematics of Statistics, Pt. 1, 3rd
ed. Princeton, NJ: Van Nostrand, p. 166, 1962.
