Kai is the most frequent word in any Greek text, and thus used by statisticians to assess authorship of ancient manuscripts based on the number of times it is used.
Because of its frequent occurrence, kai is sometimes abbreviated in Greek manuscripts and in signage, by a ligature (comparable to Latin &), written as ϗ (uppercase variant Ϗ; Coptic variant ⳤ), formed from kappa (κ) with an extra lower stroke.
The number of common words which express a general relation ('and', 'in', 'but', 'I', 'to be') is random with the same distribution at least among the same genre.
2nd Thessalonians, Titus, and Philemon were excluded because they were too short to give reliable samples.
[3] This article incorporates material from Econ 7800 class notes by Hans G. Ehrbar, which is licensed under GFDL.