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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:

(more…)

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Some variables are straightforward to measure without error – blood pressure, number of arrests, whether someone knew a word in a second language.

But many – perhaps most –  are not. Whenever a measurement has a potential for error, a key criterion for the soundness of that measurement is reliability.

Think of reliability as consistency or repeatability in measurements. (more…)

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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…)

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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…)

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In this video I will answer a question from a recent webinar, Random Intercept and Random Slope Models.

We are answering questions here because we had over 500 people live on the webinar so we didn’t have time to get through all the questions.

If you missed the webinar live, this and the other questions in this series may make more sense if you watch that first. It was part of our free webinar series, The Craft of Statistical Analysis, and you can sign up to get the free recording, handout, and data set at this link:

http://TheCraftofStatisticalAnalysis.com/random-intercept-random-slope-models

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In this video I will answer a question from a recent webinar, Random Intercept and Random Slope Models.

We are answering questions here because we had over 500 people live on the webinar so we didn’t have time to get through all the questions.

If you missed the webinar live, this and the other questions in this series may make more sense if you watch that first. It was part of our free webinar series, The Craft of Statistical Analysis, and you can sign up to get the free recording, handout, and data set at this link:

http://TheCraftofStatisticalAnalysis.com/random-intercept-random-slope-models

No comments yet