This book, Statistical Methods in Psychological and Educational Research is written with a definite aim of fulfilling the needs of the Post-graduate students and the researchers of various disciplines, like Psychology, Education, Home Science, Sociology, Child Development and Population Studies. Every research work needs to be interpreted in terms of statistical measures to show how far the results are accurate and reliable. But, what type of Statistical methods are to be applied and how the results are to be interpreted and analysed? These are the fundamental problems that every student or the researcher confronts. This book tries to solve all such problems in simple manner. Duncan's Range Test is a multi-group design, a recent development for all types of researches, presented in this book with the respective statistical tables. This statistic is a supplement and it may substitute the Analysis of Variance and the T test when the mean differences are smaller. Therefore, this book may serve as a textbook and also as the most valuable practical guide or manual to the researchers and to the students of Postgraduate studies of various disciplines.