chi-square
UK[ˈkaɪ skweə]US[ˈkaɪ skwer]
n
a statistical method used to test the difference between observed data and expected data, or to test the independence of two variables.
n
the value calculated from this test, which follows a specific probability distribution.
Morpheme Breakdown
chi
square
chi
square
Etymology
the term is a modern statistical construct, combining the name of the greek letter 'chi' (χ) with the english word 'square'. it originates from karl pearson's 1900 paper, where he introduced the chi-squared test. the 'chi' refers to the greek letter used to denote the test statistic in its mathematical formulation, while 'square' indicates that the statistic involves squaring the differences between observed and expected frequencies. thus, the term literally means "chi squared," directly describing the mathematical operation central to the test.
Analysis
Structure: chi + square
chi (greek; the name of the 22nd letter of the greek alphabet, χ) + square (english; from old french 'esquarre', meaning a geometric figure with four equal sides; here used in its mathematical sense of a number multiplied by itself).
Examples
the researcher used a chi-square test to determine if there was a significant relationship between smoking habits and lung disease.
a high chi-square value suggests that the observed data deviates substantially from the theoretical model.
the results of the chi-square analysis were presented in a contingency table.