Data on Display

Abstract

Types of data page 3 " Data " is a catchall term. But data comes in a number of varieties, and it's important to distinguish among these varieties. The Pareto chart page 7 The Pareto chart is a simple but flashy presentation method for categorical data. The dot diagram page 10 The dot diagram is a primitive display device for quantitative data. It can only be used for relatively small numbers of data points. The stem-and-leaf display page 12 This simple display for quantitative data can be constructed by hand. It's an approximation to a histogram (bar chart), and it facilitates the hand calculation of the median and the quartiles. It gives a quick visual impression of the data while still providing considerable detail. The boxplot page 18 This graphical device for quantitative data is effective for comparing two or more groups. The boxplot utilizes the median and the quartiles. Boxplot pathologies page 22 Boxplots can sometimes look weird. Here are some examples, along with the reasons why they happen.