In an era where data is ubiquitous, the ability to critically evaluate statistical information is more important than ever. This guide provides a structured overview of the common sources of error in statistics, designed to enhance your data literacy.The book systematically explores the challenges that arise at every stage of the statistical process, from data collection to presentation. It begins by examining errors in data collection and preparation, with a detailed look at sample bias. You will learn about the consequences of selective sampling, non-response, and self-selection. The text also addresses survivorship bias, explaining how focusing only on success cases can lead to skewed conclusions, and discusses inaccuracies that arise from measurement and recording errors.Moving on to statistical analysis, the book untangles common logical fallacies. It provides a clear distinction between correlation vs causation, demonstrating the impact of confounding variables and how to identify spurious relationships. A dedicated section addresses the manipulation of statistical significance, including practices like p-hacking and the selective reporting of results.Furthermore, the guide delves into cognitive biases that affect interpretation, such as confirmation bias and the base rate fallacy. It also clarifies how visual deception can occur in data presentation. You will learn how to spot misleading graphs and understand the manipulative effects of truncated axes, inappropriate chart types, and the omission of crucial context.The final section is dedicated to building practical skills. It offers methods for spotting statistical errors by critically questioning data origins, performing plausibility checks, and analyzing underlying assumptions. By exploring these fundamental sources of error, this guide equips you with the tools necessary for a more informed and critical engagement with data.For this book, we have used modern technologies – including Artificial Intelligence and individually developed software solutions. They were used in many phases of the creation process: from brainstorming and research to writing and editing, as well as quality assurance and the design of the decorative illustrations.Our goal is to offer you a reading experience that is particularly coherent and contemporary. The content of this book is, for the most part, AI-generated.