Não paramétrico statistics refers to a branch of statistics that does not rely on data belonging to any particular distribution. Unlike parametric statistics, which assumes that data follows a certain distribution (like the distribuição normal), non-parametric methods are more flexible and can be applied to a wide range of tipos de dados, including ordinal and dados nominais.
These methods are particularly useful when dealing with small sample sizes or when the underlying distribution of the data is unknown or cannot be assumed. Non-parametric techniques include a variety of statistical tests and procedures, such as the Wilcoxon rank-sum test, Kruskal-Wallis test, and Spearman’s rank coeficiente de correlação. These tests often focus on the ranks of data rather than the data values themselves, which makes them less sensitive to outliers and skewed distributions.
Non-parametric statistics can be advantageous in many practical applications, such as in ciências sociais and medical research, where data may not meet the assumptions necessary for parametric tests. Despite their flexibility, non-parametric methods generally have less statistical power than their parametric counterparts when the parametric assumptions are satisfied, meaning they may require larger sample sizes to achieve the same level of confidence in results.
No geral, as estatísticas não paramétricas oferecem ferramentas valiosas para dados útil quando métodos paramétricos tradicionais podem não ser aplicáveis ou adequados.