Analytics | Learn SAS | Programming Tips

Rick WicklinMarch 22, 2023 0

Partial correlation: controlling for confounding variables

A data analyst wanted to estimate the correlation between two variables, but he was concerned about the influence of a confounding variable that is correlated with them. The correlation might affect the apparent relationship between main two variables in the study. A common confounding variable is age because young people

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Programming Tips

Peter StyliadisMarch 21, 2023 0

Getting Started with Python Integration to SAS® Viya® - Part 15 - Count Missing Values in a CAS Table

Welcome to the continuation of my series Getting Started with Python Integration to SAS Viya. In this post I'll discuss how to count missing values in a CAS table using the Python SWAT package. Load and prepare data First, I connect my Python client to the distributed CAS server and named

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Data Management | Programming Tips

Melodie RushMarch 20, 2023 0

Getting Started with Python Integration to SAS Viya for Predictive Modeling - Index

Welcome to my series on getting started with Python integration to SAS Viya for predictive modeling. Exploring Data - Learn how to explore the data before fitting a model Working with Dates - Learn how to format a SAS Date and calculate a new column Imputing Missing Values - Learn

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Data Management | Programming Tips

Melodie RushMarch 20, 2023 0

Getting Started with Python Integration to SAS Viya for Predictive Modeling - Exploring Data

Welcome to the first post in my series Getting Started with Python Integration to SAS Viya for Predictive Modeling. I'm going to dive right into the content assuming you have minimal knowledge on SAS Cloud Analytic Services (CAS), CAS Actions and Python. For some background on these subjects, refer to

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Learn SAS | Programming Tips

Rick WicklinMarch 20, 2023 0

Estimate a Markov transition matrix from historical data

In a previous article about Markov transition matrices, I mentioned that you can estimate a Markov transition matrix by using historical data that are collected over a certain length of time. A SAS programmer asked how you can estimate a transition matrix in SAS. The answer is that you can

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Analytics | Learn SAS | Programming Tips

Rick WicklinMarch 15, 2023 0

Fitting a distribution to an expert's opinion: An application of the metalog distribution

Most homeowners know that large home improvement projects can take longer than you expect. Whether it's remodeling a kitchen, adding a deck, or landscaping a yard, big projects are expensive and subject to a lot of uncertainty. Factors such as weather, the availability of labor, and the supply of materials,

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Analytics | Learn SAS | Programming Tips

Rick WicklinMarch 13, 2023 0

Use the metalog distribution in SAS

A previous article describes the metalog distribution (Keelin, 2016). The metalog distribution is a flexible family of distributions that can model a wide range of shapes for data distributions. The metalog system can model bounded, semibounded, and unbounded continuous distributions. This article shows how to use the metalog distribution in

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Learn SAS | Programming Tips

Rick WicklinMarch 8, 2023 0

How Newton calculated pi to 16 decimal places

Happy Pi Day! Every year on March 14th (written 3/14 in the US), people in the mathematical sciences celebrate "all things pi-related" because 3.14 is the three-decimal approximation to π ≈ 3.14159265358979.... Modern computer methods and algorithms enable us to calculate 100 trillion digits of π. However, I think it

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Learn SAS | Programming Tips

Rick WicklinMarch 6, 2023 0

The variance of the sums of variables

Undergraduate textbooks on probability and statistics typically prove theorems that show how the variance of a sum of random variables is related to the variance of the original variables and the covariance between them. For example, the Wikipedia article on Variance contains an equation for the sum of two random

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Analytics | Programming Tips

Rick WicklinMarch 1, 2023 0

The distribution of the difference between two beta random variables

A SAS programmer wanted to compute the distribution of X-Y, where X and Y are two beta-distributed random variables. Pham-Gia and Turkkan (1993) derive a formula for the PDF of this distribution. Unfortunately, the PDF involves evaluating a two-dimensional generalized hypergeometric function, which is not available in all programming languages.

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Analytics | Programming Tips

Rick WicklinFebruary 27, 2023 0

Compute hypergeometric functions in SAS

In applied mathematics, there is a large collection of "special functions." These function appera in certain applications, often as the solution to a differential equation, but also in the definition of probability distributions. For example, I have written about Bessel functions, the complete and incomplete gamma function, and the complete

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Programming Tips

Ron CodyFebruary 22, 2023 0

DATA Step or PROC? It depends...

Which SAS technique should you use? Consider how often the program is to be run, your comfort level and more.

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Analytics | Learn SAS | Programming Tips

Rick WicklinFebruary 20, 2023 0

Simulate from a bounded distribution that has a specified mean

A SAS programmer asked for help to simulate data from a distribution that has certain properties. The distribution must be supported on the interval [a, b] and have a specified mean, μ, where a < μ < b. It turns out that there are infinitely many distributions that satisfy these

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Programming Tips

Peter StyliadisFebruary 13, 2023 0

Getting Started with Python Integration to SAS® Viya® - Part 14 - CAS Table to DataFrame

Welcome to the continuation of my series Getting Started with Python Integration to SAS Viya. In this post I'll discuss how to bring a distributed CAS table back to your Python client as a DataFrame. In this example, I'm using Python on my laptop (Python client) to connect to the

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Analytics | Programming Tips

Rick WicklinFebruary 13, 2023 0

Estimate the pth root of a Markov transition matrix

You can use a Markov transition matrix to model the transition of an entity between a set of discrete states. A transition matrix is also called a stochastic matrix. A previous article describes how to use transition matrices for stochastic modeling. You can estimate a Markov transition matrix by using

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Data Visualization | Learn SAS | Programming Tips

Rick WicklinFebruary 8, 2023 0

A random walk inside a heart

SAS programmers love to make special graphs for Valentine's Day. In fact, there is a long history of heart-shaped graphs and love-inspired programs written in SAS! Last year, I added to the collection by showing how a ball bounces on a heart-shaped billiards table. This year, I create a similar

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Programming Tips | SAS Administrators

Joe FurbeeFebruary 7, 2023 0

Authentication to SAS Viya: a couple of approaches

In my blog series regarding SAS REST APIs (you can read all of my posts on this topic here) I outlined how to integrate SAS analytical capabilities into applications. I detailed how to construct REST calls, build body parameters and interpret the responses. I've not yet covered authentication for the

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Analytics | Programming Tips

Peter StyliadisFebruary 7, 2023 0

Getting started with Python integration to SAS® Viya® - Part 13 - Loading a Client-Side CSV File into CAS

Welcome to the continuation of my series Getting Started with Python Integration to SAS Viya. In previous posts, I discussed how to connect to the CAS server, how to execute CAS actions, and how your data is organized on the CAS server. In this post I'll discuss loading client-side CSV files into

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Learn SAS | Programming Tips

Rick WicklinFebruary 6, 2023 0

How to use Git to share SAS programs

This article is about how to use Git to share SAS programs, specifically how to share libraries of SAS IML functions. Some IML programmers might remember an earlier way to share libraries of functions: SAS/IML released "packages" in SAS 9.4m3 (2015), which enable you to create, document, share, and use

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Data Visualization | Learn SAS | Programming Tips

Rick WicklinFebruary 1, 2023 0

Colorblind-safe palettes in SAS

SAS supports the ColorBrewer system of color palettes from the ColorBrewer website (Brewer and Harrower, 2002). The ColorBrewer color ramps are available in SAS by using the PALETTE function in SAS IML software. The PALETTE function supports all ColorBrewer palettes, but some palettes are not interpretable by people with color

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Data Visualization | Learn SAS | Programming Tips

Rick WicklinJanuary 30, 2023 0

Tips for making colorblind-safe statistical graphs

Did you know that about 8% of the world's men are colorblind? (More correctly, 8% of men are "color vision deficient," since they see colors, but not all colors.) Because of the "birthday paradox," in a room that contains eight men, the probability is 50% that at least one is

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Learn SAS | Programming Tips

Rick WicklinJanuary 25, 2023 0

Write to the log from SAS IML programs

I previously discussed how to use the PUTLOG statement to write a message from the DATA step to the log in SAS. The PUTLOG statement is commonly used to write notes, warnings, and errors to the log. This article shows how to use the PRINTTOLOG subroutine in SAS IML software

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Learn SAS | Programming Tips

Rick WicklinJanuary 23, 2023 0

Use the PUTLOG statement to write errors, warning, and notes to the SAS log

Many experienced SAS programmers use the PUT statement to write messages to the log from a DATA step. But did you know that SAS supports the PUTLOG function, which is another way to write a message to the log? I use the PUTLOG statement in the DATA step for the

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Analytics | Programming Tips

Peter StyliadisJanuary 17, 2023 0

Getting started with Python integration to SAS® Viya® - Part 12 - Count of Unique Values

Welcome to the continuation of my series Getting Started with Python Integration to SAS Viya. In previous posts, I discussed how to connect to the CAS server, working with CAS actions and CASResults objects, and how to summarize columns. Now it's time to focus on how to get the count of unique values

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Analytics | Programming Tips

Rick WicklinJanuary 16, 2023 0

Simulate data from a logistic regression model: How the intercept parameter affects the probability of the event

This article shows that you can use the intercept parameter to control the probability of the event in a simulation study that involves a binary logistic regression model. For simplicity, I will simulate data from a logistic regression model that involves only one explanatory variable, but the main idea applies

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Programming Tips | SAS Administrators

Leonid BatkhanJanuary 11, 2023 0

Automatic cloning of SAS metadata user groups and roles

SAS expert Leonid Batkhan demonstrates how to automatically replicate/clone metadata users’ groups and roles from one user to another.

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Analytics | Learn SAS | Programming Tips

Rick WicklinJanuary 11, 2023 0

12 blog posts from 2022 that deserve a second look

In a previous article, I presented some of the most popular blog posts from 2022. In general, popular articles deal with elementary topics that have broad appeal. However, I also write articles about advanced topics. The following articles didn't make the Top 10 list, but they deserve a second look.

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Programming Tips

Ron CodyJanuary 10, 2023 0

Understanding the _TYPE_ variable in output data sets

When you use PROC MEANS or PROC SUMMARY to create a summary data set and include a CLASS statement, SAS includes two variables, _FREQ_ and _TYPE_, in the output data set. This blog shows you two ways to interpret and use _TYPE_ using the data set Shoes in the SASHELP

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Analytics | Learn SAS | Programming Tips

Rick WicklinJanuary 4, 2023 0

Top 10 posts from The DO Loop in 2022

Last year, I wrote almost 90 articles for The DO Loop blog. My most popular articles were about SAS programming, data visualization, statistics and data analysis, and matrix computations. If you missed these articles when I published them—or if you want to read them again!— here is the "Reader's Choice

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Programming Tips

Peter StyliadisDecember 22, 2022 0

Creating a Microsoft Excel report using SAS, Python and SQL!

The addition of the PYTHON procedure and Python editor in SAS Viya enables users to execute Python code in SAS Studio. This new capability in SAS Viya adds another tool to SAS's existing collection. With this addition I thought, how can I utilize this new found power? In this example,

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