When you have attribute data, you tally responses into categories and determine the frequency or percentage in each category. Two widely used graphs, the bar chart and the Pareto diagram, will be discussed.
A bar chart presents each category of an attribute type variable as a bar whose length is the frequency or percentage of values falling into a category. The data in Table 3.1 represent a summary table of the number of errors and the type of error for laboratory tests.
|Social Security Number||226||49.8|
|Date of Birth||58||12.8|
|Source: Extracted from N. B. Riebling, ...|