Annotating visualizations with reference lines, fitted curves, and error bars

Adding lines to a visualization can significantly enhance the information you wish to convey. You can add horizontal or vertical lines to indicate boundaries or various statistical measures. You can also add curve fits that "smooth" the data and show you the overall trend. Let's return to the stock market data that was first used in Chapter 3, Impactful Dashboards! For example, we may want to smooth out the fluctuations in the stock market and look at its overall performance over time. The example in this section will show you how to do that.

Fitted curves

Refer to Chapter 3, Impactful Dashboards!, if you've not already loaded...