This book is an introduction to the fundamental concepts and applications of statistics in the analysis and interpretation of experimental data. Basic aspects of statistics are explained without entering into mathematical complexities, yet every effort has been made to avoid any sacrifice of precision, clarity and essential details of the principles involved. The application of every statistical method is amply illustrated by numerous worked-out examples totalling nearly 100. Some comparatively modern innovation like the the G test, Wilcoxon's revised non-parametric methods and Gabriel's method for multiple a Posterior comparison are introduced side by side with the methods. The applicabilities as well as the limitations of each method are emphasized. Item analysis, reliability and validity of psychological tests, standardization, norms and important standard scores such as T, C and stanine have been described in required details. Statistical tables are appended at the end of the book. Curves and diagrams are used in good numbers to help understanding.