Adding model fits to a ggplot2 scatter plot

Описание: How to add model fits to an existing graphic. i.e., how to add a "smooth" to a graphic.

An html version of this material used in the video can be downloaded to your current working direction (run `getwd()` in the Console to see where this is) by running the following command in the R Console:

download.file("https://raw.githubusercontent.com/jfr...",
"03-basic-data-viz-with-ggplot2.nb.html")

The raw R Markdown code used to generate the html file can be obtained by toggling the "Code" box in the upper-right corner of the html file and selecting "Download Rmd".