This simple chi-square calculator tests for association between two categorical variables - for example, sex (males and females) and smoking habit (smoker and non-smoker).

*Requirements*

- Random sample
- Observations must be independent of each other (so, for example, no matched pairs)
- Cell count must be 5 or above for each cell in a 2 x 2 contingency table

*Null Hypothesis*

The null hypothesis asserts the independence of the variables under consideration (so, for example, gender and voting behavior are independent of each other).

*Equation*