Visualization of the Ordinary Least Squares estimation of slope for a simple linear model
- Left pane illustrates line (defined by center of mass and slope) and individual squared residuals
- Right pane illustrates sum of squared residuals as function of slope
I originally created this back in 2010 using only base R and in less than 100 lines of code. The multipage pdf was added to a set of LaTeX slides made with beamer and brought to live using the animate package.
Today I edited the code ever so slightly converting comments from Danish to English, and then I converted the resulting multipage pdf to an animated gif using a webservice, https://ezgif.com/.
IMHO a nice touch is the shading of the overlapping squares using the alpha argument in the rgb() function.
Please feel free to improve upon this. A few things come to mind:
- Create the gif using code
- Move some of the calculation outside loop (although they are quite light)
- In this setup the range of slopes to explore is set by a single handpicked parameter (delta)
- Implement in ggplot2 ;-)