This chapter covers statistical methods for evaluating tree robustness. Bootstrapping is introduced as a resampling technique to assess confidence in clades. The logic, procedure and interpretation of bootstrap values are explained, with emphasis on their limitations. Hypothesis testing in phylogenetics is discussed through likelihood ratio tests, alternative topological tests and model selection. The chapter highlights how different hypotheses can be tested in a phylogenetic framework. By integrating statistics into phylogenetics, it underscores the importance of measuring uncertainty rather than assuming trees as absolute truths.