STATISTICS-I

Statistics – I play a crucial role in modern data analysis, providing
the foundation for understanding and interpreting data in various
fields. This book, structured according to the recommended
syllabus of the University of Madras (UNOM), offers a
comprehensive guide to the fundamental concepts and techniques
in statistics.
In Unit I, we begin with an introduction to the basic definitions and
methods of statistics, exploring the processes of complete
enumeration and sample surveys. This unit also delves into the
collection of data, emphasizing the distinctions between primary
and secondary data, and introduces key concepts such as variables
and their classification.
Unit II focuses on the visual representation of data through

diagrams and graphs. The types of diagrams, including two-
dimensional and three-dimensional representations, are covered in

detail. The unit also provides an in-depth look at the graphical
representation of frequency distributions, including histograms,
frequency polygons, frequency curves, and ogives.
In Unit III, we shift our focus to data analysis, particularly
univariate data. This unit covers measures of central tendency such
as the arithmetic mean, median, and mode, providing a solid
foundation for summarizing and understanding data.
Unit IV addresses measures of dispersion or variation, which are
essential for understanding the spread and variability of data. Key
concepts such as range, quartile deviation, mean deviation,
standard deviation, and coefficient of variation are thoroughly
explained.

Finally, Unit V explores the relationships between variables
through the study of correlation and the association of attributes.
This unit covers scatter diagrams, Karl Pearson’s coefficient of
correlation, Spearman’s rank correlation coefficient, and the
correlation coefficient for bivariate frequency tables.
To support the theoretical knowledge presented in this book,
previous year question papers are included, providing students with
valuable practice and insights into the application of statistical
methods.
This book is designed to serve as a comprehensive resource for
students and professionals alike, offering clear explanations,
practical examples, and a structured approach to mastering the
essentials of statistics. Whether you are a novice seeking to build a
strong foundation or an experienced practitioner looking to refine
your skills, this book is a valuable tool for your statistical journey.
We hope that this book will inspire and equip you with the
knowledge and confidence to navigate the world of data with
precision and insight.
While every effort has been made to ensure the accuracy and
comprehensiveness of this book, we acknowledge that errors and
omissions can occur. We welcome feedback from readers to help
us correct any mistakes and improve future editions. Please feel
free to contact us with any corrections, suggestions, or comments.