'''Term Frequency Exponent''' \alpha sets how the made-up words on a page are spread. The words are numbered by rank r = 1, 2, \ldots, V, with V = 10 \times Document Length, and each word of a page is drawn with

P(r) \propto r^{-\alpha}

so the word of rank 1 is 2^{\alpha} times as likely as the word of rank 2, and 10^{\alpha} times as likely as the word of rank 10. This is Zipf's law; \alpha = 1 is the law as measured on real text. The choices run from 0.8 to 2.0.