<P> The term significance does not imply importance here, and the term statistical significance is not the same as research, theoretical, or practical significance . For example, the term clinical significance refers to the practical importance of a treatment effect . </P> <P> Statistical significance dates to the 1700s, in the work of John Arbuthnot and Pierre - Simon Laplace, who computed the p - value for the human sex ratio at birth, assuming a null hypothesis of equal probability of male and female births; see p - value § History for details . </P> <P> In 1925, Ronald Fisher advanced the idea of statistical hypothesis testing, which he called "tests of significance", in his publication Statistical Methods for Research Workers . Fisher suggested a probability of one in twenty (0.05) as a convenient cutoff level to reject the null hypothesis . In a 1933 paper, Jerzy Neyman and Egon Pearson called this cutoff the significance level, which they named α . They recommended that α be set ahead of time, prior to any data collection . </P> <P> Despite his initial suggestion of 0.05 as a significance level, Fisher did not intend this cutoff value to be fixed . In his 1956 publication Statistical methods and scientific inference, he recommended that significance levels be set according to specific circumstances . </P>

What is meant by 0.05 level of significance