I am a beginner and still needs suggestion what kind of packages that I have to perform to make data like this?
I really appreciate your help.
Please answer!
Try adding a geom_vline(xintercept = 80). This adds lines at specific x values. You can change the transparency of the lines as well by adding alpha = 0.5. You would then have to fill in between the lines with color. I would look at theme() and try messing with the panel.background or panel.grid to change the color of the background and grid lines. Hope this helps at least a little!