Recently I was honored to be interviewed by Mamadou Dakouo for his company DataSteps. I was asked three questions: How did I learn SAS? What advice do I have for someone who wants to become a “top SAS programmer?” What is my favorite SAS procedure? My answers were In graduate school Be a self-starter […]
Tag: SAS
Using Excel for Data Entry
This article shows you how to enter data so that you can easily open in statistics packages such as R, SAS, SPSS, or jamovi (code or GUI steps below). Excel has some statistical analysis capabilities, but they often provide incorrect answers. For … Continue reading →
Gartner’s 2018 Take on Data Science Tools
I’ve just updated The Popularity of Data Science Software to reflect my take on Gartner’s 2018 report, Magic Quadrant for Data Science and Machine Learning Platforms. To save you the trouble of digging though all 40+ pages of my report, … Continue reading →
Did I add that CA Certificate to the SAS Trusted CA Bundle?
Sometimes I forget whether I’ve added our internal site root and intermediate CA certificates to the Trusted CA Bundle that SAS® Software applications use. Sometimes I also forget the command I can use to find out whether I did! 😉 As is ofte…
jamovi for R: Easy but Controversial
jamovi is software that aims to simplify two aspects of using R. It offers a point-and-click graphical user interface (GUI). It also provides functions that combines the capabilities of many others, bringing a more SPSS- or SAS-like method of programming … Continue reading →
Type I error rates in two-sample t-test by simulation
What do you do when analyzing data is fun, but you don’t have any new data? You make it up.
This simulation tests the type I error rates of two-sample t-test in R and SAS. It demonstrates efficient methods for simulation, and it reminders the reader not to take the result of any single hypothesis test as gospel truth. That is, there is always a risk of a false positive (or false negative), so determining truth requires more than one research study.
A type I error is a false positive. That is, it happens when a hypothesis test rejects the null hypothesis when in fact it is not true. In this simulation the null hypothesis is true by design, though in the real world we cannot be sure the null hypothesis is true. This is why we write that we “fail to reject the null hypothesis” rather than “we accept it.” If there were no errors in the hypothesis tests in this simulation, we would never reject the null hypothesis, but by design it is normal to reject it according to alpha, the significance level. The de facto standard for alpha is 0.05.
R
First, we run a simulation in R by repeatedly comparing randomly-generated sets of normally-distributed values using the two-sample t-test. Notice the simulation is vectorized: there are no “for” loops that clutter the code and slow the simulation.
For more posts like this, see Heuristic Andrew.
Condition execution on row count
Use this code as a template for scenarios when you want to change how a SAS program runs depending on whether a data set is empty or not empty. For example, when a report is empty, you may want to not send an email with what would be a blank report. In other words, the report sends only when it has information.
On the other hand, you may want to send an email when a data set is empty if that means an automated SAS program had an error that requires manual intervention.
In general, it’s good practice in automated SAS programs to check the size of a data sets in case they are empty or otherwise have the wrong number of observations. With one easy tweak, you could check for a specific minimum number of observations that is greater than zero. (This is left as an exercise for the reader.)
For more posts like this, see Heuristic Andrew.
SAS Management Console on HiDPI Windows 10
A few days ago I installed SAS Management Console 9.4 M4 and Metacoda Plug-ins 6.0 R4 on a Microsoft Surface Pro running Windows 10. After launching SAS Management Console, and logging in, it looked very odd. All of the icons and text were very close together and the text was hard to read. Here’s a … Continue reading “SAS Management Console on HiDPI Windows 10”