Introduction

This introduction presents an overview of the key concepts discussed in the subsequent chapters of this book. The book explores the question of sex differences in risk preferences from an empirical, statistical point of view. It explains why we tend to gravitate toward stereotypes and the much simpler (though misleading) question of "different or not?" Insights from philosophy, linguistics, and cognitive psychology are examined. The chapter introduces "Statistical tools for analyzing similarity and difference", with simple, non-technical examples as well as more detailed technical notes, the Index of Similarity (IS), Cohen's d, and the Common Language Effect Size (CLES). It reviews "Statistical tools for inference and the detection of bias", basic concepts of statistical inference and the use of the p-value for the non-technical reader, and then discusses statistical fallacies common even among experienced researchers. The chapter also explores the issue of individual-level versus aggregate-level "difference".