An anecdotal, inside guide to how statistics are compiled and used in professional sports--which may generate more numbers than anything this side of Wall Street or Washington, D.C. Friedman obviously delights in the offbeat occupation he entered in 1966 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, stats 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; who should try for the winning field goal in the final seconds of a close basketball game; and whether a pass or run should be called in certain third-down situations. Friedman is aware that enthusiasts can carry statistics to nonsensical extremes, and at the end of one yarn he notes: ""I'll have to check. . . but I may hold the record for table-pounding among right-handed New York statisticians in close hockey games."" Almost haft 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. Armchair quarterbacks and even casual fans will pore over Friedman's account of the numbers games played in pro sports.