When given a list of numbers, we are often asked to find its statistical range. The statistical range of a list of numbers is the highest value minus the lowest value, and it describes how much the list of numbers can vary. Along with the statistical range, it's important to understand statistical mean, statistical median and statistical mode and how they apply to a list of numbers.
In your Algebra class you're going to be working with two different meanings for the word range. One word range means the output values for the possible y values of a function. Don't worry about that for now, we're talking about range as it applies to data sets or statistics. The range of a data set is the highest value minus the lowest value. It's a really useful way for looking at the spread of information and it becomes useful when you guy are making graphs. When you're making graphs you want to figure out like how many boxes do I need to skip, how much data is gong to be on my graph. So the range helps you in lots of different ways and it's easy to calculate highest value minus the lowest value.