Statistical Software

Member Training: How to Avoid Common Graphical Mistakes

December 1st, 2019 by

Good graphs are extremely powerful tools for communicating quantitative information clearly and accurately.

Unfortunately, many of the graphs we see today confuse, mislead, or deceive the reader.

These poor graphs result from two key limitations. One is a graph designer who isn’t familiar with the principles of effective graphs. The other is software with a poor choice of default settings.

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Member Training: What’s the Best Statistical Package for You?

February 1st, 2019 by

Choosing statistical software is part of The Fundamentals of Statistical Skill and is necessary to learning a second software (something we recommend to anyone progressing from Stage 2 to Stage 3 and beyond).

You have many choices for software to analyze your data: R, SAS, SPSS, and Stata, among others. They are all quite good, but each has its own unique strengths and weaknesses.

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The Secret to Importing Excel Spreadsheets into SAS

January 21st, 2019 by

My poor colleague was pulling her hair out in frustration today.

You know when you’re trying to do something quickly, and it’s supposed to be easy, only it’s not? And you try every solution you can think of and it still doesn’t work?

And even in the great age of the Internet, which is supposed to know all the things you don’t, you still can’t find the answer anywhere?

Cue hair-pulling.

Here’s what happened: She was trying to import an Excel spreadsheet into SAS, and it didn’t work.

Instead she got:

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Interpreting Interactions in Linear Regression: When SPSS and Stata Disagree, Which is Right?

December 20th, 2017 by

Sometimes what is most tricky about understanding your regression output is knowing exactly what your software is presenting to you.

Here’s a great example of what looks like two completely different model results from SPSS and Stata that in reality, agree.

The Model

I ran a linear model regressing “physical composite score” on education and “mental composite score”.

The outcome variable, physical composite score, is a measurement of one’s physical well-being.   The predictor “education” is categorical with four categories.  The other predictor, mental composite score, is continuous and measures one’s mental well-being.

I am interested in determining whether the association between physical composite score and mental composite score is different among the four levels of education. To determine this I included an interaction between mental composite score and education.

The SPSS Regression Output

Here is the result of the regression using SPSS:

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The Advantages of RStudio

September 26th, 2017 by

There are multiple ways to interface with R. Some common interfaces are the basic R GUI, R Commander (the package “Rcmdr” that you use on top of the basic R GUI), and RStudio.

When I first started to learn to use R, I was bound and determined to use the basic R GUI.

As someone who was already used to programming in SAS, I wasn’t looking for a (more…)


What Really Makes R So Hard to Learn?

September 19th, 2017 by

If you are like I was for a long time, you have avoided learning R.

You’ve probably heard that there’s a steep learning curve. Or noticed that the available documentation is not necessarily user-friendly.

Frankly, both things are true, to some extent.

R is Open-Source

The best and worst thing about R is that it is open-source. So there is no single (more…)