Whay is a readability formulas?

Try looking here:

http://www.google.com/search?as_q=&hl=en&num=10&btnG=Google+Search&as_epq=readability+formulas&as_oq=&as_eq=&lr=&as_ft=i&as_filetype=&as_qdr=all&as_nlo=&as_nhi=&as_occt=title&as_dt=i&as_sitesearch=&as_rights=&safe=images