I previously wrote about the advantages of adding horizontal and vertical reference lines to a graph. You can also add a diagonal reference line to a graph. The SGPLOT procedure in SAS supports two primary ways to add a diagonal reference line: The LINEPARM statement enables you to specify a
Data tell a story. A purpose of data visualization is to convey that story to the reader in a clear and impactful way. Sometimes you can let the data "speak for themselves" in an unadorned graphic, but sometimes it is helpful to add reference lines to a graph to emphasize
I have written several articles about how to work with continuous probability distributions in SAS. I always emphasize that it is important to be able to compute the four essential functions for working with a statistical distribution. Namely, you need to know how to generate random values, how to compute
During an epidemic, such as the coronavirus pandemic of 2020, the media often shows graphs of the cumulative numbers of confirmed cases for different countries. Often these graphs use a logarithmic scale for the vertical axis. In these graphs, a straight line indicates that new cases are increasing at an
A cumulative curve shows the total amount of some quantity at multiple points in time. Examples include: Total sales of songs, movies, or books, beginning when the item is released. Total views of blog posts, beginning when the post is published. Total cases of a disease for different countries, beginning
During an outbreak of a disease, such as the coronavirus (COVID-19) pandemic, the media shows daily graphs that convey the spread of the disease. The following two graphs appear frequently: New cases for each day (or week). This information is usually shown as a histogram or needle plot. The graph
When you create a graph by using the SGPLOT procedure in SAS, usually the default tick locations are acceptable. Sometimes, however, you might want to specify a set of custom tick values for one or both axes. This article shows three examples: Specify evenly spaced values. Specify tick values that
A colleague recently posted an article about how to use SAS Visual Analytics to create a circular graph that displays a year's worth of temperature data. Specifically, the graph shows the air temperature for each day in a year relative to some baseline temperature, such as 65F (18C). Days warmer
The ROC curve is a graphical method that summarizes how well a binary classifier can discriminate between two populations, often called the "negative" population (individuals who do not have a disease or characteristic) and the "positive" population (individuals who do have it). As shown in a previous article, there is
The purpose of this article is to show how to use SAS to create a graph that illustrates a basic idea in a binary classification analysis, such as discriminant analysis and logistic regression. The graph, shown at right, shows two populations. Subjects in the "negative" population do not have some
