Chi-square (X^2) is a statistical method used to analyse nominal (frequency) data rather than quantitative data obtained from continuous variables such as height, temperature etc. (scores) and requires between-subjects design. It is used when we want to compare frequency counts of different categories to see whether there is an association between the variables. For example:
- Are gay people more likely to be religious than straight people? (2 variables: religious belief and sexual orientation)
- Are male schoolchildren more likely to pursue academic career in maths than female ones? (variables: gender and programme of choice to study in university).
As always, I will explain the logic of the Chi-Square, show the calculation using an example and talk about Degrees of Freedom and Significance Testing.
- Are gay people more likely to be religious than straight people? (2 variables: religious belief and sexual orientation)
- Are male schoolchildren more likely to pursue academic career in maths than female ones? (variables: gender and programme of choice to study in university).
As always, I will explain the logic of the Chi-Square, show the calculation using an example and talk about Degrees of Freedom and Significance Testing.