This is the fourth edition of the textbook Inferential Statistics: Hypothesis Testing and Decision-making, first published in 1995. It has been renamed Inferential Data Analysis to emphasise the role of statistics as a tool in the research process rather than an end in itself. The book adopts a decision-making approach, aiming to contextualise statistics for making decisions about hypotheses.This edition has been substantially revised, both in content and in alignment with the latest versions of SPSS and Excel. It now includes:-an overview of basic descriptive statistics,-guidance on using SPSS and Excel,-a focus on effective presentation of statistical results in research papers, and-a section on advanced multivariate techniques.It also places greater emphasis on effect-size statistics rather than relying solely on significance testing."My very well-thumbed copy of 'my little green stats bible' has been constantly referenced since I bought it in 1996. This book, on its own, helped me overcome my fear of stats..."- Former student at the University of the Western Cape, now a lecturer at UNISA.