1. Introduction to Statistics and Data Visualisation

This chapter introduces the reader to the fundamentals of descriptive statistics and data visualisation. Descriptive statistics focus on the development of methods for describing a given data set. They can be divided into two main groups: measures of central tendency, which examine the average behaviour of the data set, and measures of dispersion, which examine the spread of the data set. Measures of central tendency, such as the mean, mode, and median, are introduced, while measures of dispersion considered include the range, standard deviation, variance, median absolute difference, and skew. Also, quantiles and outliers are introduced as ways to describe a data set. Data visualisation focuses on developing a set of rules for effectively displaying data visually. Common data visualisation methods such as bar charts, histograms, pie charts, line charts, time series plots, box-and-whisker plots, scatter plots, probability plots, tables, and sparkplots are explained with detailed examples and methods of construction. The different approaches are illustrated with suitable examples, including a comprehensive analysis of a data set from a friction factor experiment. By the end of this chapter, the reader should be able to apply the principles of data description and visualisation to meaningfully portray the key properties of a given data set.