For anyone a bit mystified that there would be multiple ways of defining "average", they're all ways to describe a 'typical' number in a dataset. I’ll list ’em below.

- mean (what many people assume 'average' means'): a sum of all the values divided by the number of values.

- median: the value that half the data set les above and half lies below

- mode: The most common value in the set

Each is appropriate to certain kinds of data distributions; using the wrong one is IMO the same as lying.

Speaking of which, if it sounds like I'm spouting gibberish, check out Huff's "How to Lie with Statistics". No hard math. It's targeted at people who can't / don't want to do that. 8th grade me was enchanted with it. Even then I realized it wasn't so much about helping me to lie (cool for an 8th grader) but in seeing when someone was using statistics to lie to me. IMO still the best intro to statistics out there.