The Handbook on Experimental Statistics has been prepared as an aid to scientists and engineers engaged in Army research and development programs, and especially as a guide and ready reference for military and civilian personnel who have responsibility for the planning and interpretation of experiments and tests relating to the performance of Army equipment in the design and developmental stages of production. The present document, section 4, is devoted to consideration and exemplification of a number of important but as yet non-standard statistical techniques, and to discussion of various other special topics. An index for the material in all four sections is placed at the end of Section 4.