The DO Loop
Statistical programming in SAS with an emphasis on SAS/IML programs![Add horizontal and vertical reference lines to SAS graphs: The REFLINE statement](https://blogs.sas.com/content/iml/files/2020/04/refline5-640x336.png)
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
![On reducing the spread of coronavirus](https://blogs.sas.com/content/iml/files/2020/04/geometriccovid-643x336.png)
Every day we face risks. If we drive to work, we risk a fatal auto accident. If we eat red meat and fatty foods, we risk a heart attack. If we go out in public during a pandemic, we risk contracting a disease. A logical response to risk is to
![The geometric distribution in SAS](https://blogs.sas.com/content/iml/files/2020/04/geometricdist2-640x336.png)
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
![Estimates of doubling time for exponential growth](https://blogs.sas.com/content/iml/files/2020/04/doublingtime3-640x336.png)
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
![Smokestack plots: A visualization technique for comparing cumulative curves](https://blogs.sas.com/content/iml/files/2020/03/smokestack1-640x336.png)
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
![How to read a cumulative frequency graph](https://blogs.sas.com/content/iml/files/2020/03/cumul1-500x336.png)
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