This chapter introduces the principles of quantitative data analysis. It starts by describing how to prepare quantitative data for analysis. The chapter then introduces a data analysis software package – JASP – and briefly explains its use. Descriptive analysis is introduced, followed by a discussion of the concept of inferential statistics, including an examination of the idea and meaning of the concept of statistical significance. A variety of statistical tests are outlined, together with guidance as to their use. The chapter then explores the correct reporting of statistical tests and concludes with a discussion of the common errors made in statistical analysis.