Visual Representation of Data

Chapter 1 covered how to identify questions, populations, and collect the data. Chapters 2, 3, and 4 discuss how to organize and summarize the data. The focus of chapter 2 is how to use visual representations such as tables, charts, and graphs to help us understand the data.

Figure 2.1: The process of statistics

When we summarize quantitative data in step 3 of the process, we will address the following 4 characteristics.

•Center- a way to describe the middle, or most typical.

•Variation- a way to describe how much the data varies.

•Distribution- a way to describe the shape of the distribution.

•Outliers- are there any highly unusual values?

In section 2.1 we will discuss visual representations of qualitative data, while section 2.2 covers visual representations of quantitative data. In section 2.3 we look at ways that graphs can be misleading.

By the end of this chapter, you will be able to

•Compute frequency and relative frequency from data

•Create frequency and relative frequency tables for qualitative data

•Create visual representations of qualitative data including

▪Pie charts

▪Bar graphs

▪Pareto charts

•Create frequency and relative frequency tables for classes of discrete or continuous data

•Create and interpret visual representations of quantitative data including:

▪Dot plots

▪Histograms

▪Stem and Leaf plots

•Identify common ways that graphs can be misleading