In this chapter the reader is introduced to the field of statistics. The chapter has three main sections: the relationship between statistics and science, basic definitions, and statistical notation and rules of rounding. Throughout the text bold type is used for the first occurrence of specialised/statistical terms (and for comments annotating parts of computer output), and italicis used for emphasis.

Statistics and scientific inquiry

Statistics are usually defined as facts and figures which summarize a data set, or the methods utilized to achieve such figures. But, as R. A. Fisher explains in his seminal book Statistical Methods for Research Workers (1991a), statistics are also the study of populations (to be defined below) and their variation. It is precisely because we wish to understand the variation present in the population of our interest that we use figures (statistics) to describe the sample with which we work.

Statistics are an integral part of science. Not only do they help the researcher to organize and interpret data, but they are also involved in the process of hypothesis testing, perhaps the main difference between science and other forms of knowledge pursuits.

Although the concepts of theory and hypothesis are extremely important in science, they are frequently defined differently in various disciplines. In this book, we define a theory as a set of hypotheses that has been tested repeatedly and not rejected. A hypothesis is defined as an explanation of observed facts, an explanation which may or may not be testable.