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Learn SAS

Learn about the latest tips, tutorials, upcoming events and certifications

Analytics | Learn SAS

Rick WicklinFebruary 5, 2024 0

Peeling a convex hull

This article looks at a geometric method for estimating the center of a multivariate point cloud. The method is known as convex-hull peeling. In two-dimensions, you can perform convex-hull peeling in SAS 9 by using the CVEXHULL function in SAS IML software. For higher dimensions, you can use the CONVEXHULL

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Learn SAS | Programming Tips

Rick WicklinJanuary 31, 2024 0

The name of the variable that contains the largest value in each row

A SAS programmer wanted to find the name of the variable for each row that contains the largest value. This task is useful for wide data sets in which each observation has several variables that are measured on the same scale. For example, each observation in the data might represent

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Learn SAS | Programming Tips

Rick WicklinJanuary 24, 2024 0

Implement Jacobi's method in SAS

In a first course in numerical analysis, students often encounter a simple iterative method for solving a linear system of equations, known as Jacobi's method (or Jacobi's iterative method). Although Jacobi's method is not used much in practice, it is introduced because it is easy to explain, easy to implement,

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Analytics | Learn SAS

Rick WicklinJanuary 22, 2024 0

Angles vs slopes: The statistics of steepness

There are two popular ways to express the steepness of a line or ray. The most-often used mathematical definition is from high-school math where the slope is defined as "rise over run." A second way is to report the angle of inclination to the horizontal, as introduced in basic trigonometry.

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Learn SAS | Programming Tips

Rick WicklinJanuary 15, 2024 0

Simulate correlated continuous and discrete variables

Statistical software provides methods to simulate independent random variates from continuous and discrete distributions. For example, in the SAS DATA step, you can use the RAND function to simulate variates from continuous distributions (such as the normal or lognormal distributions) or from discrete distributions (such as the Bernoulli or Poisson).

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Learn SAS | Programming Tips

Ron CodyJanuary 10, 2024 0

Using the BXOR Function to Encode and Decode Text

SAS expert Ron Cody recently published a fiction novel, The Enigma Terrorists, in which SAS code plays a key role.

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Analytics | Learn SAS

Rick WicklinJanuary 8, 2024 0

Reporting statistics for unobserved levels of categorical variables

An unobserved category is one that does not appear in a sample of data. For example, in a small sample of US voters, you are likely to observe members of the major political parties, but less likely to observe members of minor or fringe parties. This can cause a headache

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Analytics | Data Visualization | Learn SAS | Programming Tips

Rick WicklinJanuary 3, 2024 0

Top 10 posts from The DO Loop in 2023

In 2023, I wrote 90 articles for The DO Loop blog. My most popular articles were about SAS programming, data visualization, and statistics. In addition, several "general interest" articles were popular, including my article for Pi Day and an article about AI chatbots. If you missed any of these articles,

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Learn SAS

Alexis MallisDecember 20, 2023 0

What is the value of SAS® certification

In today’s competitive marketplace and quickly evolving technological landscape, keeping knowledge current and developing hard skills has become more important than ever – and students and professionals alike are searching for opportunities to stand out from the crowd. In the analytics space, many are turning to career certificates in data

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Advanced Analytics | Analytics | Data Management | Data Visualization | Learn SAS | Students & Educators | Work & Life at SAS

Adriana RojasDecember 19, 2023 0

"Cada vez existen más asignaturas vinculadas a temas analíticos en todos los sectores”

La información certera es la base sobre la que se edifican las empresas, especialmente en un contexto en el que la preparación y la resiliencia son cada vez más importantes. Con el aumento en la cantidad de datos disponibles y la necesidad de aprovecharlos para tener mejores resultados, también hemos

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SAS Spain | Spanish

Data for Good | Learn SAS

Riad GydienDecember 19, 2023 0

4 reasons SAS is empowering young minds to code in South Africa

In the classrooms of South Africa, students are learning how to code with hopes of creating future opportunities for themselves. Coding4Mandela, an initiative honoring Nelson Mandela, strives to instill coding and technological skills in youth. The belief is that empowering young minds with digital literacy enhances their educational and professional

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Analytics | Learn SAS

Rick WicklinDecember 19, 2023 0

The difference between frequencies and weights in a correlation analysis

Statistical software often includes supports for a weight variable. Many SAS procedures make a distinction between integer frequencies and more general "importance weights." Frequencies are supported by using the FREQ statement in SAS procedures; general weights are supported by using the WEIGHT statement. An exception is PROC FREQ, which contains

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Analytics | Learn SAS | Students & Educators

Cinzia Gianfiori

Cinzia GianfioriDecember 18, 2023 0

Certificazioni SAS e SAS Academic Specialization per favorire il contatto tra giovani studenti e aziende

Nel corso degli anni SAS ha costruito una solida partnership con il mondo accademico. Oggi collaboriamo con più di 40 università italiane e siamo presenti all’interno di percorsi di studio per formare giovani studenti e studentesse su temi come analytics, intelligenza artificiale e machine learning, stimolando la loro curiosità, il loro senso

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Learn SAS | Machine Learning

Sharad SaxenaDecember 14, 2023 0

New SAS Training Course: Statistics You Need to Know for Machine Learning

Developing an accurate understanding of statistics will help you build robust machine learning models that are optimized for a given business problem. SAS launched a new course that provides a comprehensive overview of the fundamentals of statistics that you'll need to start your data science journey. This course is also a prerequisite to many courses in the SAS data science curriculum.

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Analytics | Learn SAS

Rick WicklinDecember 13, 2023 0

Estimate polychoric correlation by maximum likelihood estimation

SAS provides many built-in routines for data analysis. A previous article discusses polychoric correlation, which is a measure of association between two ordinal variables. In SAS, you can use PROC FREQ or PROC CORR to estimate the polychoric correlation, its standard error, and confidence intervals. Although SAS provides a built-in

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Analytics | Learn SAS

Rick WicklinDecember 11, 2023 0

What is polychoric correlation?

Correlation is a statistic that measures the association between two variables. When two variables are positively correlated, low values of one variable tend to be associated with low values of the other variable. Medium values and high values are similarly associated. For negative correlation, the association is flipped: low values

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Learn SAS | Predictions

Alexis MallisDecember 6, 2023 0

Optimize learning for sustained employee growth in 2024 with these 5 tips

As the idea of professional growth has changed, organizations have shifted their approach to learning and development (L&D) for employees. However, we’ve noticed this shift is more focused on identifying employees’ training needs to increase motivation and retain top talent. Throughout 2024, we expect to experience a continuation of this

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Data Visualization | Learn SAS

Rick WicklinDecember 6, 2023 0

10 tips for creating effective statistical graphics

These are a few of my favorite things. —Maria in The Sound of Music For my annual Christmas-themed post, I decided to forgo fractal Christmas trees and animated greeting cards and instead present a compilation of some of my favorite data visualization tips for advanced SAS users. Hopefully, this

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Analytics | Learn SAS | Programming Tips

Rick WicklinDecember 4, 2023 0

Bivariate normal probability in SAS

A previous article discussed how to compute probabilities for the bivariate standard normal distribution. The standard bivariate normal distribution with correlation ρ is denoted BVN(0,ρ). For any point (x,y), you can use the PROBBNRM function in SAS to compute the probability that the random variables (X,Y) ~ BVN(0,ρ) is observed

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Learn SAS

Jongman JeongNovember 24, 2023 0

SAS Job Execution Web 애플리케이션 훑어보기

이번 글에서는 SAS의 Job Execution에 대해서 알아보려고 합니다. 개념과 접속방법, 실행방법, 편집방법을 예제를 활용해 간단히 알아보겠습니다. 1. Job Execution 소개 SAS Job Execution Web Application은 작업을 생성, 관리 및 실행하는 데 사용되는 웹 기반 클라이언트입니다. Java로 작성된 이 애플리케이션은 서버에서 실행되는 강력한 분석 및 프리젠테이션 프로시저와 함께 데이터에 대한 액세스를

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Learn SAS | Programming Tips

Rick WicklinNovember 15, 2023 0

On resizing an array when an index is out of bounds

Converting a program from one language to another can be a challenge. Even if the languages share many features, there is often syntax that is valid in one language that is not valid in another. Recently, a SAS programmer was converting a program from R to SAS IML. He reached

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Data Visualization | Learn SAS

Rick WicklinNovember 13, 2023 0

Tip: Avoid alphabetical order for a categorical axis in a graph

Howard Wainer, who used to write the "Visual Revelations" column in Chance magazine, often reminded his readers that "we are almost never interested in seeing Alabama first" (2005, Graphic Discovery, p. 72). His comment is a reminder that when we plot data for a large number of categories (states, countries,

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Data Visualization | Learn SAS | Programming Tips

Rick WicklinNovember 8, 2023 0

4 ways to display an inset that contains statistics on a SAS graph

Sometimes it is helpful to display a table of statistics directly on a graph. A simple example is displaying the number of observations and the mean or median on a histogram. In SAS, the term inset is used to describe a table that is displayed on a graph. This article

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Analytics | Learn SAS | Programming Tips

Rick WicklinNovember 6, 2023 0

Standard errors for maximum likelihood estimation

In several previous articles, I've shown how to use SAS to fit models to data by using maximum likelihood estimation (MLE). However, I have not previously shown how to obtain standard errors for the estimates. This article combines two previous articles to show how to obtain MLE estimates and the

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Learn SAS | Programming Tips

Rick WicklinNovember 1, 2023 0

The distribution of the sample median for normal data

A previous article shows how to use Monte Carlo simulation to approximate the sampling distribution of the sample mean and sample median. When x ~ N(0,1) are normal data, the sample mean is also normal, and there are simple formulas for the expected value and the standard error of the

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Learn SAS | Programming Tips

Rick WicklinOctober 30, 2023 0

The distribution of the sample median

An elementary course in statistics often includes a discussion of the sampling distribution of a statistic. The canonical example is the sampling distribution of the sample mean. For samples of size n that are drawn from a normally distribution (X ~ N(μ, σ)), the sample mean is normally distributed as

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Learn SAS | Programming Tips

Rick WicklinOctober 25, 2023 0

Quantiles of the generalized birthday problem

A previous article discusses the birthday problem and its generalizations. The classic birthday problem asks, "In a room that contains N people, what is the probability that two or more people share a birthday?" The probability is much higher than you might think. For example, in a room that contains

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Learn SAS | Programming Tips

Rick WicklinOctober 23, 2023 0

The generalized birthday problem

The birthday-matching problem (also called the birthday paradox or simply the birthday problem), is a classic problem in probability. Simply stated, the birthday-matching problem asks, "If there are N people in a room, what is the chance that two of them have the same birthday?" The problem is sometimes called

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Data for Good | Learn SAS

Alexis MallisOctober 16, 2023 0

A stronger world: 3 ways SAS® users can wield data for good

Across a wide variety of industries, SAS users are leaning into the power of data to glean relevant insights and identify new opportunities. Through analytics, they are solving complex problems, discovering practical insights, and making a difference in their fields and communities. How can others join their efforts and use

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Learn SAS | Programming Tips

Rick WicklinOctober 16, 2023 0

On the evaluation of the function exp(x) - 1

Recently I wrote about numerical analysis problem: the accurate computation of log(1+x) when x is close to 0. A naive computation of log(1+x) loses accuracy if you call the LOG function, which is why the SAS language provides the built-in LOG1PX for this computation. In addition, I showed that you

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