Countless professionals and students who use statistics in their work rely on the multi-volume Encyclopedia of Statistical Sciences as a superior and unique source of information on statistical theory, methods, and applications. This new edition (available in both print and on-line versions) is designed to bring the encyclopedia in line with the latest topics and advances made in statistical science over the past decade--in areas such as computer-intensive statistical methodology, genetics, medicine, the environment, and other applications. Written by over 600 world-renowned experts (including the editors), the entries are self-contained and easily understood by readers with a limited statistical background. With the publication of this second edition in 16 printed volumes, the Encyclopedia of Statistical Sciences retains its position as a cutting-edge reference of choice for those working in statistics, biostatistics, quality control, economics, sociology, engineering, probability theory, computer science, biomedicine, psychology, and many other areas. The Encyclopedia of Statistical Sciences is also available as a 16 volume A to Z set. Volume 15: W-Z.