The chi-square distribution is a statistical distribution commonly used in hypothesis testing and confidence interval estimation. It is particularly useful for analyzing categorical data and assessing how well observed data fit expected outcomes. The distribution is defined by its degrees of freedom, which are determined by the number of categories minus one. In practical applications, the chi-square test helps researchers determine if there is a significant association between variables in a contingency table. As the sample size increases, the chi-square distribution approaches a normal distribution, making it easier to interpret results in larger datasets.