If the observed probability is equal to or less than some small value selected before you conduct your test, typically .05 (and referred to as alpha), reject the null hypothesis and accept your...

If the observed probability is equal to or less than some small value selected before you conduct your test, typically .05 (and referred to as alpha), reject the null hypothesis and accept your evaluation hypothesis. Alpha also is known as the level of significance, and tells us how probable it is that we are incorrectly rejecting the null hypothesis (if alpha is .05, then larger values would include .06, .10, .25, etc., and smaller values would include .04, .01, or .001). If the null hypothesis is rejected, this means the outcome was statistically significant.