significance level

The degree to which a value that has been obtained through systematic data collection will not occur by chance. In research reporting, this level is expressed numerically to indicate the number of times out of a specified number of samplings that the result would probably occur by chance. In the social sciences, the significance levels are most often .01, .05, or .001, even though any other figure could be used as well. For example, if the .05 level is used, a specified outcome would occur by chance five times among 100 samplings.