Probability mass functions

Now when you're dealing with discrete data, that little nuance about having infinite numbers of possible values goes away, and we call that something different. So that is a probability mass function. If you're dealing with discrete data, you can talk about probability mass functions. Here's a graph to help visualize this:

For example, you can plot a normal probability density function of continuous data on the black curve shown in the graph, but if we were to quantize that into a discrete dataset like we would do with a histogram, we can say the number 3 occurs some set number of times, and you can actually say the number 3 has a little over 30% chance of occurring. So a probability mass function is the way that we visualize the probability of discrete data occurring, and it looks a lot like a histogram because it basically is a histogram.