Blog Archives

Christopher Salahub on Markov Chains – The Central Equilibrium – Episode 2

Christopher Salahub on Markov Chains – The Central Equilibrium – Episode 2

It was a great pleasure to talk to Christopher Salahub about Markov chains in the second episode of my new talk show, The Central Equilibrium!  Chris graduated from the University of Waterloo with a Bachelor of Mathematics degree in statistics.  He just finished an internship in data development at Environics Analytics, and he is starting […]

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Store multiple strings of text as a macro variable in SAS with PROC SQL and the INTO statement

Store multiple strings of text as a macro variable in SAS with PROC SQL and the INTO statement

I often need to work with many variables at a time in SAS, but I don’t like to type all of their names manually – not only is it messy to read, it also induces errors in transcription, even when copying and pasting.  I recently learned of an elegant and efficient way to store multiple […]

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Use the LENGTH statement to pre-set the lengths of character variables in SAS – with a comparison to R

Use the LENGTH statement to pre-set the lengths of character variables in SAS – with a comparison to R

I often create character variables (i.e. variables with strings of text as their values) in SAS, and they sometimes don’t render as expected.  Here is an example involving the built-in data set SASHELP.CLASS. Here is the code: data c1;      set sashelp.class;      * define a new character variable to classify someone as tall or […]

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Sorting correlation coefficients by their magnitudes in a SAS macro

Sorting correlation coefficients by their magnitudes in a SAS macro

Theoretical Background Many statisticians and data scientists use the correlation coefficient to study the relationship between 2 variables.  For 2 random variables, and , the correlation coefficient between them is defined as their covariance scaled by the product of their standard deviations.  Algebraically, this can be expressed as . In real life, you can never […]

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Potato Chips and ANOVA, Part 2: Using Analysis of Variance to Improve Sample Preparation in Analytical Chemistry

Potato Chips and ANOVA, Part 2: Using Analysis of Variance to Improve Sample Preparation in Analytical Chemistry

In this second article of a 2-part series on the official JMP blog, I use analysis of variance (ANOVA) to assess a sample-preparation scheme for quantifying sodium in potato chips.  I illustrate the use of the “Fit Y by X” platform in JMP to implement ANOVA, and I propose an alternative sample-preparation scheme to obtain […]

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Potato Chips and ANOVA in Analytical Chemistry – Part 1: Formatting Data in JMP

Potato Chips and ANOVA in Analytical Chemistry – Part 1: Formatting Data in JMP

I am very excited to write again for the official JMP blog as a guest blogger!  Today, the first article of a 2-part series has been published, and it is called “Potato Chips and ANOVA in Analytical Chemistry – Part 1: Formatting Data in JMP“.  This series of blog posts will talk about analysis of […]

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Odds and Probability: Commonly Misused Terms in Statistics – An Illustrative Example in Baseball

Odds and Probability: Commonly Misused Terms in Statistics – An Illustrative Example in Baseball

Yesterday, all 15 home teams in Major League Baseball won on the same day – the first such occurrence in history.  CTV News published an article written by Mike Fitzpatrick from The Associated Press that reported on this event.  The article states, “Viewing every game as a 50-50 proposition independent of all others, STATS figured the […]

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Odds and Probability: Commonly Misused Terms in Statistics – An Illustrative Example in Baseball

Odds and Probability: Commonly Misused Terms in Statistics – An Illustrative Example in Baseball

Yesterday, all 15 home teams in Major League Baseball won on the same day – the first such occurrence in history.  CTV News published an article written by Mike Fitzpatrick from The Associated Press that reported on this event.  The article states, “Viewing every game as a 50-50 proposition independent of all others, STATS figured the […]

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Using and Producing a Control Chart in R for Statistical Process Control – An Application in Analytical Chemistry

Using and Producing a Control Chart in R for Statistical Process Control – An Application in Analytical Chemistry

Update on Wednesday, August 5, 2015: I am considering retracting this blog post based on my disagreement with Daniel Harris’ approach to building the warning and action lines in a control chart.  Please see my replies to Jake Yeager and Lee Kennedy in the comments section for my thoughts.  Your patience is appreciated; please stay […]

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Mathematical Statistics Lesson of the Day – Basu’s Theorem

Mathematical Statistics Lesson of the Day – Basu’s Theorem

Today’s Statistics Lesson of the Day will discuss Basu’s theorem, which connects the previously discussed concepts of minimally sufficient statistics, complete statistics and ancillary statistics.  As before, I will begin with the following set-up. Suppose that you collected data in order to estimate a parameter .  Let be the probability density function (PDF) or probability […]

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