For development of any branch of science correctness and precision is a must. The same principle applies also to the public health - with the recent advances in health sciences especially in public health, there is an increasing requirement of objectivity. If data are proper and accurate in objectivity, they can be properly processed and correctly interpreted. The correct processing and interpretation can lead to definite conclusions, which may stand the tests of significance & will play significant role in the advancement of that science.The purpose of this monograph is to familiarize with the preliminary biostatistics so that it can be conveniently used. For every field of investigation or enquiry, the first step is planning and then collection of data. The next step is classification, analysis and testing for accuracy by statistical methods.