Chapter 2 What Data Looks Like and Summarizing Data

This chapter moves us to more practical matters, namely working with actual data. Once you get familiar with what real data sets look like and how they are organized, you will learn how to summarize the information contained within variables. We can do that through tables and through graphs. Both reflect the distribution of a variable (a concept which we’ll discuss extensively from Chapter 3 on), which is the way the observations/data points are distributed across a variable’s categories. (For example, counting how many of your friends don’t have siblings, how many have one sibling, how many have two siblings, etc, and writing the information down will give you the (frequency) distribution of the variable number of siblings you friends have.)

We start with frequency tables, and explore the summary information contained within. We end the chapter with the way we can visually display variables (i.e., their distribution) and the discussion of what type of graph (a pie chart, a bar graph, or a histogram) is most appropriate for variables at different levels of measurement.