Monday, August 1, 2016

Anscombe's Quartet

No, Wikipedia isn't a proper resource for our students to cite. But it is not without merit.

For example, I think the information it provides on Anscombe's quartet is very useful. This example provides four data distributions. For each, the means and variances for both the X and Y variables are identical. The correlations between X and Y, and the regression lines, are also identical.

This is the descriptive/inferential data that applies to each of the four graphs

I have seen variations upon this in textbooks over the years, but typically they just show how different distributions can have the same mean and standard deviation. I think this example goes the extra mile by including r and the regression line.

How to use in class:

-Graphs aren't for babies. They can be an essential part of understanding your data.
-Outliers are bad!
-The original data is also included at the Wikipedia entry if you would like your students to create these graphs in class.