This book has been designed for undergraduate students to meet the course on Statistical Methods and their Applications of B.Sc. Computer Science and B.Sc. Biochemistry curriculum of University of Madras. The book provides a simple, clear and exhaustive treatment of the subject in simple non-mathematical format. The text in this volume covers the topics such as definition and meaning of the term statistics, measures of central tendency, measures of dispersion, meaning of probability, addition theorem, multiplication theorem, Bayes theorem, random variable and its moments, moment generating function, central limit theorem and Tchebecheve's inequality.