It's time for another blog post about ciphers. As I indicated in my previous blog post about substitution ciphers, the classical substitution cipher is no longer used to encrypt ultra-secret messages because the enciphered text is prone to a type of statistical attack known as frequency analysis. At the root
The Third PharmaSUG-China conference was held in Beijing last week, and I had the pleasure to attend this excellent conference along with a record number of attendees. On Thursday, I presented two 1/2 day seminars on ODS Graphics. One titled "Advanced Topics in GTL" and another titled "Complex Clinical Graphs
Often we need to plot the response values for binary cases of a classifier. The graph below is created to simulate one seen at http://www.people.vcu.edu/ web site of the shock index for subjects with or without a pulmonary embolism. In this case, the data is simulated for illustration purposes only. There
When I create a graph of data that contains a categorical variable, I rarely want to display the categories in alphabetical order. For example, the box plot to the left is a plot of 10 standardized variables where the variables are ordered by their median value. The ordering makes it
While I was working on my recent blog post about two-dimensional binning, a colleague asked whether I would be discussing "the new hexagonal binning method that was added to the SURVEYREG procedure in SAS/STAT 13.2." I was intrigued: I was not aware that hexagonal binning had been added to a
The ODS ExcelXP tagset has served us well over the years. It provides a reliable method to get formatted SAS output into Microsoft Excel workbooks, where the business world seems to like to live. And it's available in Base SAS, which means that you don't need SAS/ACCESS to PC Files
When you create a histogram with statistical software, the software uses the data (including the sample size) to automatically choose the width and location of the histogram bins. The resulting histogram is an attempt to balance statistical considerations, such as estimating the underlying density, and "human considerations," such as choosing
SAS 9.4 maintenance release M2 was released early in August. This release contains some exciting new features in GTL and SG Procedures. In this article, I will describe some of the new options added to the existing plot statements. Note, I will use the SG examples here, but these are
Often there are questions from users on creating histogram using a Log X axis. One such question came up this weekend, where a user wanted a histogram of her data using log axis. Before we get into her specific case, let us first clarify what we may want to see
In her article Creating Spaghetti Plots Just got Easy, Lelia McConnell has provided us a glimpse into some new useful features in the SAS 9.4M2 release. The term Spaghetti plots generally refers to cases where time series plots have to be identified by multiple group classifications. The support for the
This article is by guest contributor Lelia McConnell, SAS Tech Support. Creating Spaghetti Plots Just Got Easy Sample 38076: “Response by patient and treatment group” illustrates how to generate a spaghetti plot using the SGPLOT procedure. Sample 40255: “Plot of study results by treatment group” illustrates how to generate a
A couple of days back, Rick Wicklin forwarded me a link to an article on the BadHessian Blog on creating a Bar Chart using six different freeware packages in R, Python and Julia. The target bar chart was one produced by the Jetpack stat module with WordPress. The graph is shown below. The unique feature of
In a previous blog post, I showed how to overlay a prediction ellipse on a scatter plot in SAS by using the ELLIPSE statement in PROC SGPLOT. The ELLIPSE statement draws the ellipse by using a standard technique that assumes the sample is bivariate normal. Today's article describes the technique
This post could be titled something like "Everything you wanted to know about Group Order in GTL - and more." The group ordering shows up in three different ways in your graph. Assignment of attributes (color, marker symbol) to group values. Position of group values in the graph. Display of the group
It is common in statistical graphics to overlay a prediction ellipse on a scatter plot. This article describes two easy ways to overlay prediction ellipses on a scatter plot by using SAS software. It also describes how to overlay multiple prediction ellipses for subpopulations. What is a prediction ellipse? A
In my four years of blogging, the post that has generated the most comments is "How to handle negative values in log transformations." Many people have written to describe data that contain negative values and to ask for advice about how to log-transform the data. Today I describe a transformation
In my previous blog post, I showed how to use log axes on a scatter plot in SAS to better visualize data that range over several orders of magnitude. Because the data contained counts (some of which were zero), I used a custom transformation x → log10(x+1) to visualize the
If you are trying to visualize numerical data that range over several magnitudes, conventional wisdom says that a log transformation of the data can often result in a better visualization. This article shows several ways to create a scatter plot with logarithmic axes in SAS and discusses some of the
Spirals are cool. And useful. We use them every day without thinking about it. Every time the road turns from a straight line to a curve, we go through a transition spiral. Spirals allow us to change curvature in a steady increasing or decreasing fashion. Without a spiral, this
Last week I showed how to use the SUBMIT and ENDSUBMIT statements in the SAS/IML language to call the SGPLOT procedure to create ODS graphs of data that are in SAS/IML vectors and matrices. I also showed how to create a SAS/IML module that hides the details and enables you
The topic of VENN diagrams had come up a while ago. At that time, I thought it may be interesting to build a proportional VENN diagram. But, reading up on VENN Diagrams, I learned that VENN diagrams represent all intersections of N sets, regardless of whether there are actually any observations in one
By now you have heard all about the SAS(R) STUDIO software that provides access to the power of SAS analytics in a Web browser. The SAS(R) University Edition is also available free for higher education teaching, learning and research. This software includes ODS Graphics software for creating graphs. You can
In my book Simulating Data with SAS, I show how to use the SAS DATA step to simulate data from a logistic regression model. Recently there have been discussions on the SAS/IML Support Community about simulating logistic data by using the SAS/IML language. This article describes how to efficiently simulate
As you develop a program in the SAS/IML language, it is often useful to create graphs to visualize intermediate results. The language supports basic statistical graphics such as bar charts, histograms, scatter plots, and so on. However, you can create more advanced graphics without leaving PROC IML by using the
At PharmaSUG 2014 in San Diego, I had the pleasure of attending "Swimmer Plot: Tell a Graphical Story of Your Time to Response Data Using PROC SGPLOT", by Stacey Phillips. In this paper, Stacey presented an interesting graph showing the effects of a study drug on patients' tumor size. Stacey
Recently, a user posed a question on how to plot stacked frequencies on a time axis. The data included frequencies of different viruses by week. The data is modified to preserve confidentiality and is shown below. The user's first instinct was to use a bar chart with stacked groups. This works for automatically computing frequencies
When teaching statistics, it is often useful to produce a normal density plot with shading under the curve. For example, consider a one-sided hypothesis test. An alpha value of .05 would correspond to a Z-score cutoff of 1.645. This means that 95% of a standard normal curve falls below a
It was almost two weeks ago that I got started making a display for lab tests for a subject, based on a graph I saw on the web for an article on this blog. This graph is a part of a larger panel display of the lab values for a
Just getting back from PharmaSUG 2014 in San Diego. The conference was great, both inside and outside. The organizers ordered up some great weather for the Padres game and also for dinner on the flight deck of the Midway Carrier. Our focus here being on graphics, we were all extremely gratified by the presentations in
Frequently you may want to modify the default colors, line patterns and symbols that are displayed on the graphics output produced by the Statistical Graphics, or SG procedures, and the Graph Template Language, GTL. Enhancements in SAS 9.4 have made that task much easier! In the examples below, we will look
