<P> In 1928, Jerzy Neyman (1894--1981) and Egon Pearson (1895--1980), both eminent statisticians, discussed the problems associated with "deciding whether or not a particular sample may be judged as likely to have been randomly drawn from a certain population": and, as Florence Nightingale David remarked, "it is necessary to remember the adjective' random' (in the term' random sample') should apply to the method of drawing the sample and not to the sample itself". </P> <P> They identified "two sources of error", namely: </P> <Dl> <Dd> (a) the error of rejecting a hypothesis that should have been accepted, and </Dd> <Dd> (b) the error of accepting a hypothesis that should have been rejected . </Dd> </Dl> <Dd> (a) the error of rejecting a hypothesis that should have been accepted, and </Dd>

An example of a type i error would be