Understanding and Applying Basic Statistical Methods Using R

Chapter 1INTRODUCTION

Why are statistical methods important? One reason is that they play a fundamental role in a wide range of disciplines including physics, chemistry, astronomy, manufacturing, agriculture, communications, pharmaceuticals, medicine, biology, kinesiology, sports, sociology, political science, linguistics, business, economics, education, and psychology. Basic statistical techniques impact your life.

At its simplest level, statistics involves the description and summary of events. How many home runs did Babe Ruth hit? What is the average rainfall in Seattle? But from a scientific point of view, it has come to mean much more. Broadly defined, it is the science, technology, and art of extracting information from observational data, with an emphasis on solving real-world problems. As Stigler (1986, p. 1) has so eloquently put it:

Modern statistics provides a quantitative technology for empirical science; it is a logic and methodology for the measurement of uncertainty and for examination of the consequences of that uncertainty in the planning and interpretation of experimentation and observation.

To help elucidate the types of problems addressed in this book, consider an experiment aimed at investigating the effects of ozone on weight gain in rats (Doksum and Sievers, 1976). The experimental group consisted of 22 seventy-day-old rats kept in an ozone environment for 7 days. A control group of 23 rats, of the same age, was kept in an ozone-free environment. The ...