The 1.2.1 version of Zipfer for Mac was available to download on the developer's website when we last checked. We cannot confirm if there is a free download of this app available. Zipfer for Mac lies within Productivity Tools, more precisely Calculators. We recommend checking the downloaded files with any free antivirus. The actual developer of this Mac application is Economy-x-Talk.
From the developer:
Zipfer is a little tool by xTalk programmer Mark Schonewille. This software retrieves data from any text file, counts the words and creates a proper data file. From the resulting data file, Zipfer can calculate a number of statistics, such as a linear regression equation expressing the relationship between rank and frequency of each word.
You may want to check out more Mac applications, such as Ratiocinator X, pearCalc or Googol, which might be related to Zipfer.