Excerpt from Manual of Mental and Physical Tests: A Book of Directions Compiled, With Special Reference to the Experimental, Study of School Children in the Laboratory or Classroom In the introductory sections of the volume, I have sought to show the general purposes of mental tests, to lay down rules for their conduct, and to explain the methods of treating data. In this connection I discuss the calculation of measures of general tendency, measures of variability, indexes of correlation, and other statistical constants. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.