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Rick WicklinAugust 11, 2025 1

What is Cohen's d statistic and how is it used? How can you compute it in SAS? This article gives some history behind Cohen's d statistic. It shows how to compute the statistic in SAS for the difference in means between two independent samples. It shows how to estimate a

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Analytics | Learn SAS | Programming Tips

Rick WicklinAugust 6, 2025 0

3 ways to estimate parameters when fitting a distribution to data

SAS provides procedures to fit common probability distributions to sample data. You can use PROC UNIVARIATE in Base SAS or PROC SEVERITY in SAS/ETS software to estimate the distribution parameters for approximately 20 common distributions, including normal, lognormal, beta, gamma, and Weibull. Since there are infinitely many distributions, you may

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Data Visualization | Learn SAS | Programming Tips

Rick WicklinJuly 28, 2025 0

How to position tick marks for months when you graph weekly data

Suppose you measure data weekly. According to the ISO standard, weeks are measured in the range 1-53, where most years have 52 weeks, but occasionally there is a "leap week." (The WEEK function in SAS implements the ISO standard to find the week-of-the-year for any date.) The heat map to

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Learn SAS | Programming Tips

Rick WicklinJuly 21, 2025 4

Strengthen your SAS skills with the WEEK function

Dating can be a challenge. No, I'm not talking about the process of finding a soulmate. I'm talking about managing days, weeks, months, and years in statistical analyses and reports! One challenge is how to number the weeks of the year. Because there are seven days in a week, 52

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Data Visualization | Learn SAS

Rick WicklinJuly 14, 2025 5

Use a lasagna plot to visualize US gas prices

I follow several data visualization experts on social media. Sometimes, I see a graph that I struggle to interpret. When that happens, I ask myself whether there is a simpler and more effective way to visualize the data. Recently, I saw an example of using a "horizon plot" to visualize

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Analytics | Learn SAS

Rick WicklinJuly 7, 2025 3

Noncentrality parameters and confidence intervals

While researching a topic on effect sizes, I learned about a SAS function that is related to noncentrality parameters. I previously wrote an article about the noncentral t distribution, which is one of several well-known distributions that contains an optional noncentrality parameter. I mentioned that the PDF, CDF, and QUANTILE

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Advanced Analytics | Learn SAS | Machine Learning

Rick WicklinJune 30, 2025 0

An application of Latin hypercube sampling to optimization

A previous article discusses a "Catch-22" paradox for fitting nonlinear regression models: You can't estimate the parameters until you fit the model, but you can't fit the model until you provide an initial guess for the parameters! If your initial guess for the parameters is not good enough, the nonlinear

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Advanced Analytics | Data Visualization | Learn SAS

Rick WicklinJune 23, 2025 0

How to add a curve to a moment-ratio diagram

I have previously written about the moment-ratio diagram as a graphical tool for modeling univariate distributions and also as a tool for examining the distribution of the skewness and kurtosis statistics for distributions. The simple moment-ratio (M-R) diagram from my book (Wicklin, 2013, Simulating Data with SAS, Chapter 16) is

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Analytics | Data Visualization | Learn SAS | Programming Tips

Rick WicklinJune 16, 2025 0

Find the orthant that contains a point

This article shows how to classify a set of high-dimensional data into orthants. An orthant is the d-dimensional generalization of a quadrant. For 2-D Euclidean space, there are four quadrants, often labeled by Roman numerals I-IV. The quadrants are open sets that are defined by the signs of each coordinate

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Learn SAS | Programming Tips

Rick WicklinJune 9, 2025 0

Generate a check digit and validate a Universal Loan Identifier in SAS

This article shows how to use SAS to implement the ISO algorithm to generate (and validate) a Universal Loan Identifier (ULI). A ULI is a long string of numbers and letters that serves as a unique identifier that is used for certain financial transactions. The ISO standard ensures that banks

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