I published 118 blog posts in 2014. This article presents my most popular posts from 2014 and late 2013.

2014 will always be a special year for me because it was the year that the SAS University Edition was launched. The University Edition means that SAS/IML is available to all students and adult learners all over the world. My article "10 tips for learning the SAS/IML language" has been popular as new programmers take advantage of this free opportunity to learn the SAS/IML language for matrix computations and data analysis.

### General math and statistics articles

Although I mostly write about statistical programming, several of my general articles on math and statistics were very popular:

- "Does this kurtosis make my tail look fat?" explains kurtosis and why long tails and fat tails matter when modeling data.
- Have you heard of an Ulam Spiral? It is a graphical way to visualize the distributions of prime numbers.
- Do you know the fundamental theorem of calculus? How about the Fundamental Theorem of Statistics?
- Speaking of fundamentals, in his 2014 ASA President's Invited Address, historian and statistician Stephen Stigler answers the question "What is statistics?" by proposing seven pillars of statistical wisdom.

### Statistical Graphics and Data Visualization

Who doesn't like to learn better ways to visualize data in SAS? The following posts generated some interesting discussions.

- You can use box plots to visualize the distributions of 100 variables in a single plot.
- When your data values range over several orders of magnitude, it is often useful to log-transform the data. I wrote about how to create a scatter plot with log-log axes and how to use the log-plus-one transformation to handle 0s in the data.
- In a similar way, you can apply a log-modulus transformation to visualize data that are both positive and negative and range over orders of magnitude.
- A frequent question on discussion forums is how to create a stacked bar chart so that each category sums to 100%. I wrote a program that shows how to create a stacked bar chart in SAS by using PROC FREQ and PROC SGPLOT.

### Visualizing Matrices

An important visualization is to visualize the data in a rectangular matrix by using a heat map:

- You can use a Graph Template Language (GTL) template to visualize a data matrix that contains a small number of unique values. The SAS/IML language makes it easy to create the heat map by using the built-in HEATMAPDISC subroutine.
- In a similar way, you can use a heat map with a continuous color ramp to visualize a matrix with many values.. In SAS/IML, you can create the heat map by using the built-in HEATMAPCONT subroutine.
- When creating a heat map or a choropleth map, it can be a challenge to choose a palette of colors. Read about how to choose a color scheme that presents an unbiased view of the data.

### Regression and data smoothers

Everyone loves a good regression tip!

- A common regression task is to evaluate a model on new explanatory variables in order to predict responses. SAS software provides five ways to "score" a regression model.
- Some people like to use cubic splines, which were popular in the 1970s, to smooth their data. Learn how to fit a cubic spline to two-dimensional data and add the spline curve to a scatter plot.
- A drawback of the cubic spline is that the smoothing parameter must be manually chosen. However, you can use nonparametric statistical techniques to add a smooth curve to a scatter plot, and these techniques provide an automated way to select the smoothing parameter.

Start your new year by (re-)reading one of these 14 popular posts from 2014. Happy New Year to all my readers!

## 2 Comments

Interesting to see the list of popular blog posts. Thanks for a great year of interesting and useful tips. I hope we get to catch up at SAS Global Forum 2015 like last year ;-) https://twitter.com/HomesAtMetacoda/status/448166819908825090

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