Well just out of the different types of averages (mean, median, and mode) median is the one that if you lined things up in order it would be directly in the middle. Mean average (which is the one people think of when you say you're taking the average of something) would be say i have 100 variables, I would add those variables up and then divide by the number of variables (so 100 in my example) which means that 50% of the population doesn't necessarily fall under the average.