English

Rick Wicklin 0
Efficient acceptance-rejection simulation

A few days ago on the SAS/IML Support Community, there was an interesting discussion about how to simulate data from a truncated Poisson distribution. The SAS/IML user wanted to generate values from a Poisson distribution, but discard any zeros that are generated. This kind of simulation is known as an

SAS Events
Waynette Tubbs 0
PROC ARIMA: Penetrating the matrix

Justin Smith and William “Gui” Zupko were looking at manufacturing data over time and wanted to know the minimum value in their dataset, and they wanted to pinpoint its exact location – the specific row and column. PROC ARIMA uses the ARIMA (auto-regressive integrated moving average) model or the ARMA

SAS Events
Christina Harvey 0
NESUG 2012 Student Scholarship winners

Congratulations to this year's NorthEast SAS Users Group Student Scholarship winners!   Student scholarships make it possible for young professionals to learn new SAS skills, meet other SAS users, hear about innovative new research, and network with other professionals from around the world. Rachel Bray, University of Maryland College Park, is pursuing a

Rick Wicklin 0
Inverse hyperbolic functions in SAS

I was recently asked, "Does SAS support computing inverse hyperbolic trigonometric functions?" I was pretty sure that I had used the inverse hyperbolic trig functions in SAS, so I was surprised when I read the next sentence: "I ask because I saw a Usage Note that says these functions are

Data Visualization
Sanjay Matange 0
Report from SCSUG 2012

Last week I attended my first SCSUG conference, this one in Houston.  Houston, the fourth most populous city in USA, is the world's capitol of the Oil and Gas industry.  So it was no surprise I met many attendees from local oil and gas related companies.  But, I also met many

Data Management
Annette Marett 0
SAS loves math: Wendy McHenry

From figuring out the optimal price a company should charge for soup to forecasting an organization's financial outcomes, each day brings a new business challenge for Wendy McHenry, systems engineer at SAS. Her "How can we help?" attitude is only part of the equation for successful customer relationships. Find out how math

Rick Wicklin 0
Constructing common covariance structures

I recently encountered a SUGI30 paper by Chuck Kincaid entitled "Guidelines for Selecting the Covariance Structure in Mixed Model Analysis." I think Kincaid does a good job of describing some common covariance structures that are used in mixed models. One of the many uses for SAS/IML is as a language

Data Visualization
Sanjay Matange 0
Density Strip Plot

In the previous post on Violin Plots, we discussed the process to create custom density plots.  This work was done in collaboration with SAS user James Marcus.  This is the second installment on the same topic - Creating Density Strip Plots.  We will use the same data and process to compute

Advanced Analytics
Rick Wicklin 0
Compute the log-determinant of a matrix

The determinant of a matrix arises in many statistical computations, such as in estimating parameters that fit a distribution to multivariate data. For example, if you are using a log-likelihood function to fit a multivariate normal distribution, the formula for the log-likelihood involves the expression log(det(Σ)), where Σ is the

Data Visualization
Sanjay Matange 0
Violin Plots

Over the past month or more, I have been in a conversation with SAS user James Marcus, on creation of some new displays for visual communication of uncertainty.  These include display of densities using a "Violin" plot, "Density Strips" and more.   With his permission, I can share some of the

1 266 267 268 269 270 326