Understanding Item Response Theory with SAS

June 18, 2019
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Understanding Item Response Theory with SAS

What is Item Response Theory? Item Response Theory (IRT) is a way to analyze responses to tests or questionnaires with the goal of improving measurement accuracy and reliability. A common application is in testing a student’s ability or knowledge. Today, all major psychological and educational tests are built using IRT.

Understanding Item...
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Reviewing SSL/TLS Certificate Chain for Active Directory Server

June 18, 2019
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Sometimes when I am setting up, or helping someone setup, identity synchronisation between the SAS® platform and Microsoft Active Directory (AD), I run into SSL/TLS certificate validation issues. I am usually using Metacoda Identity Sync, but it c...
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Compress – Keep Writable

June 17, 2019
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varname = compress(varname, , 'kw');The modifier “k” stands for ‘KEEP’ and the modifier “w” stands for ‘WRITABLE’. When compress function is used in combination of K & W modifiers, it keeps all the writable characters which means it deletes all the...
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Influential observations in a linear regression model: The DFBETAS statistics

June 17, 2019
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Influential observations in a linear regression model: The DFBETAS statistics

My article about deletion diagnostics investigated how influential an observation is to a least squares regression model. In other words, if you delete the i_th observation and refit the model, what happens to the statistics for the model? SAS regression procedures provide many tables...
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Adding Metacoda Custom Tasks Capabilities for SAS Enterprise Guide

June 14, 2019
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When you install Metacoda Custom Tasks for use in SAS® Enterprise Guide® and the SAS® Add-In for Microsoft Office you may find you don’t see the new menu items you expected in the Tools menu: There are 2 main reasons why they may be...
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Leave-one-out statistics and a formula to update a matrix inverse

June 12, 2019
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Leave-one-out statistics and a formula to update a matrix inverse

For linear regression models, there is a class of statistics that I call deletion diagnostics or leave-one-out statistics. These observation-wise statistics address the question, "If I delete the i_th observation and refit the model, what happens to the statistics for the model?" For example:...
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New related resource initiative in the SAS Help Center

June 11, 2019
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New related resource initiative in the SAS Help Center

Sometimes the questions are complicated, and the answers are simple. - Dr. Seuss It seems appropriate that this blog include a Dr. Seuss quote about learning when discussing a new simple, yet deceivingly powerful initiative to help SAS customers with their journey to discover...
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Deploying the Full SAS Viya Stack in Kubernetes

June 10, 2019
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Deploying the Full SAS Viya Stack in Kubernetes

This article is a follow-on to a recent post from Jeff Owens, Getting started with SAS Containers. In that post, Jeff discussed building and running a single container for a SAS Viya runtime/IDE. Today we will go through how to build and run the...
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5 reasons to use PROC FORMAT to recode variables in SAS

June 10, 2019
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5 reasons to use PROC FORMAT to recode variables in SAS

Recoding variables can be tedious, but it is often a necessary part of data analysis. Almost every SAS programmer has written a DATA step that uses IF-THEN/ELSE logic or the SELECT-WHEN statements to recode variables. Although creating a new variable is effective, it is...
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