The oddities of the bigram "ed"

[Jorge_Stolfi]

Culpepers total rk occurrences: 379/2 = 189 & 190. And that's 1321 words per page.  76%

Seems right.  My version has N=222 occurrences of "rk", hence my suggestion would be N/2 = 111 pages.  My version has 123832 words, so it would be 1115 words/page.  

It is hard to tell whether "rk" is anomalous in your plot because all the rare digraphs, including "rk", are squeezed into the few mm near the left margin.

Maybe the graphs would be more legible if the vertical axis was changed to the percentage of pages without the digraph, and both axes were in log scale.  Then I guess that you would get a more or less straight line, similar to the Zipf plot in log-log scale.

If you say that "rk" occurs in only 76% of the pages, instead of the expected 86%, that would already indicate uneven distribution.  Not as dramatic as ed, but it would show how topic can cause the uneven distribution of certain digraphs.

All the best, --stolfi