Statistics is the science of learning from data. Data are numerical or qualitative descriptions of objects that we want to study. In this chapter, we will master the art of examining data.

The methods detailed in this chapter will help answer questions such as

• What are the most important factors that influence the choice of a credit card?
• How can we describe characteristics of cryptocurrencies that have raised more than $100 million in their Initial Coin Offering (ICO)?
• How can we describe the distribution of IQ scores for a group of sixth-graders?

We begin in Section 1.1 with some basic ideas about data. We will learn about the different types of data and how data sets are organized.

Section 1.2 starts our process of learning from data by looking at graphs. These visual displays give us a picture of the overall patterns in a set of data. We have excellent software tools that help us make these graphs. However, it takes a little experience and a lot of judgment to study the graphs carefully and to explain what they tell us about our data.

Section 1.3 continues our process of learning from data by computing numerical summaries. These sets of numbers describe key characteristics of the patterns that we see in our graphical summaries.

The final section in this chapter helps us make the transition from data summaries to statistical models such as the well-known Normal distributions that are used to draw conclusions and to make predictions.