An anecdotal, inside guide to how statistics are compiled and used in professional sports. Friedman obviously delights in his offbeat occupation as house statistician for the New York Mets. Drawing upon personal experience in four major-league sports--basketball, football, and hockey as well as baseball--he manages to convey a lot of technical information in consistently winning fashion. Samples of actual statistical reports and summary score sheets come with clear explanations of all the finer points and, often, with hilarious stories about how the stats have worked for or against people in pro sports. For the fans, batting averages, yards gained rushing, goals scored, assists, and other figures are keys to the performance of teams and competitors. But, Friedman points out, stas also can contribute to the success or failure of athletes, coaches, and front-office personnel. Statistics, for instance, can indicate how a pitcher should throw to a particular batter in the late innings with men on base; or, who should try for the winning field goal in the final seconds of a close basketball game. Almost half the book is devoted to baseball, ""a statistical paradise,"" since events are isolated and can be precisely logged. By contrast, the flow of action is more or less constant in basketball, football, and hockey--the other sports reviewed--and, as Friedman explains, there are difficulties involved in giving credit where it's due. A top number for armchair quarterbacks and even casual fans.