Definition
In statistics, 'nonparametric' describes tests or models that DON'T assume a specific distribution for the data. It's like having a flexible recipe that works no matter what kind of ingredients you have. These tests are useful when the data doesn't follow a normal distribution, or when you have limited information about the population. Nonparametric tests are generally less powerful than parametric tests when the assumptions of parametric tests are met. Think of it as a more 'robust' method, meaning it works reliably under a wider range of conditions. This flexibility is essential when dealing with messy, real-world data. 🌍