Book excerpt: In A Mathematician at the Ballpark, professor Ken Ross reveals the math behind the stats. This lively and accessible book shows baseball fans how to harness the power of made predictions and better understand the game. Using real-world examples from historical and modern-day teams, Ross shows: • Why on-base and slugging percentages are more important than batting averages • How professional odds makers predict the length of a seven-game series • How to use mathematics to make smarter bets A Mathematician at the Ballpark is the perfect guide to the science of probability for the stats-obsessed baseball fans—and, with a detailed new appendix on fantasy baseball, an essential tool for anyone involved in a fantasy league.