For a time series { y1, y2, ..., yN }, the difference operator computes the difference between two observations. The kth-order difference is the series { yk+1 - y1, ..., yN - yN-k }. In SAS, the DIF function in the DATA step computes differences between observations. The DIF function

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Tags: Matrix Computations, time series, Uncategorized

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Last week I showed how to represent a Markov transition matrix in the SAS/IML matrix language. I also showed how to use matrix multiplication to iterate a state vector, thereby producing a discrete-time forecast of the state of the Markov chain system. This article shows that the expected behavior of

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Tags: Matrix Computations, time series, Uncategorized

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Many computations in elementary probability assume that the probability of an event is independent of previous trials. For example, if you toss a coin twice, the probability of observing "heads" on the second toss does not depend on the result of the first toss. However, there are situations in which

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Tags: Matrix Computations, time series, Uncategorized

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We recently had a flooding event at Jordan Lake where the water rose almost 20 feet above normal. This blog details that flooding event in both photos and graphs. If you're intrigued by weather, boats, or lakes then this blog's for you! In NC's Research Triangle Park area, there are basically two

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Tags: analytics, flooding, time series, Uncategorized

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With a major election coming next year, I was wondering if there have been any shifts & changes in the voters in my state. This seems like an interesting opportunity for some data analysis, eh!?! To get you into the spirit of elections, here's an "I Voted" sticker from my friend

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Tags: analytics, election, map, politics, time series, Uncategorized

Posted in SAS | Comments Off on How to build a customized voter registration data viewer

I saw an interesting graph on dadaviz.com that claimed Italians had gone from drinking twice as much as Americans in 1970, to less than Americans in recent years. The data analyst in me just had to "independently verify" this factoid ... But before I get into the technical part of this

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Tags: alcohol, analytics, time series, Uncategorized

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A facebook friend posted the picture reproduced above-- it makes the case that President Obama has been a successful creator of jobs, and also paints GW Bush as a president who lost jobs. Another friend pointed out that to be fair, all of Bush's presi...

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Tags: abline(), axis statement, Bureau of Labor Statistics, col option, date formats, href option, job creation, mtext(), offset option, plot.ts(), PROC GPLOT, reflabel option, time series, ts()

Posted in SAS | Comments Off on Example 9.11: Employment plot

A facebook friend posted the picture reproduced above-- it makes the case that President Obama has been a successful creator of jobs, and also paints GW Bush as a president who lost jobs. Another friend pointed out that to be fair, all of Bush's presi...

Read more »

Tags: abline(), axis statement, Bureau of Labor Statistics, col option, date formats, href option, job creation, mtext(), offset option, plot.ts(), PROC GPLOT, reflabel option, time series, ts()

Posted in SAS | Comments Off on Example 9.11: Employment plot