What's all this about "discrete" & "cumulative" probability?

When you start digging into mathematical probability you'll soon bump into terms like "discrete probability distribution" and "cumulative probability distribution". MathHammer tools, apps and websites will also sometimes use these terms and sometimes they'll just assume you know what they mean!

Now I'm a web developer, not a mathematician, so here's my attempt at explaining what you need to know in layman's terms:

When you use UnitCrunch the "discrete probability distribution" is represented by the blue bar graph. Each bar shows the percentage of times that an individual result occurred over all of the simulations performed. All of the percentages represented by the bar graph should add up to 100%. It's "discrete" because only integer values are considered (all of the expected dice results will be integers).

The "cumulative probability distribution" is the pinky-purple line graph. It displays the percentage chance of a result occurring but also adds all of the chances of a "better" result occurring (hence why it's "cumulative").

That should be enough to get by on UnitCrunch and in MathHammer more generally. If you're after further detail I suggest checking out something like the Wikipedia entry for "Probability distribution".