Wiktionary
empirical rule
n. (context statistics singulare tantum English) (synonym of 68-95-99.7 rule the 68-95-99.7 rule English)
Usage examples of "empirical rule".
And thus I ask with reference to that empirical rule of association, which must always be admitted if we say that everything in the succession of events is so entirely subject to rules that nothing ever happens without something preceding it on which it always follows,—.