Since the paired notions of type I errors (Type1 Error) (or "FalsePositive-s") and type II errors (Type2 Error) (or "FalseNegative-s") that were introduced by Neyman and Pearson are now widely used, their choice of terminology ("errors of the first kind" and "errors of the second kind"), has led others to suppose that certain sorts of mistake that they have identified might be an "error of the third kind", "fourth kind", etc. http://en.wikipedia.org/wiki/Type_I_and_type_II_errors
In 1957, Allyn W. Kimball, a statistician with the Oak Ridge National Laboratory, proposed a different kind of error to stand beside "the first and second types of error in the theory of testing hypotheses". Kimball defined this new "error of the third kind" as being "the error committed by giving the right answer to the Wrong Problem" (1957, p. 134).
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