This video explains how to overlay histogram plots in R for 3 common cases: overlaying a histogram with a normal curve, overlaying a histogram with a density curve, and overlaying a histogram with a second data series plotted on a … Continue reading →
Video: Overlay Histogram in R (normal, density, another series) is an article from

Zero Inflated Models and Generalized Linear Mixed Models with R.
Zuur, Saveliev, Ieno (2012).