chi-by-eye

English

Etymology

Alluding to the χ² test ("chi squared test") used to formally test a statistical hypothesis.

Noun

chi-by-eye (uncountable)

1. (humorous) the practice of deciding between statistical models based on a plot, rather than a formal procedure.
   • 2007, William H. Press, Saul A. Teukolsky, William T. Vetterling, Brian P. Flannery, Numerical Recipes: The Art of Scientific Computing, page 774:

     They deem a fit acceptable if a graph of data and model "looks good." This approach is known as chi-by-eye. Luckily, its practitioners get what they deserve.

   • 2011, Steven P. Greiner, Ben Graham Was a Quant : Raising the IQ of the Intelligent Investor, page 16:

     Their business prospects and earnings are correlated, and this can be observed by visually plotting their stock prices. Statisticians often call this "chi by eye."

Related terms

• guesstimate