“A picture is worth 1000 words”
For some reason, most people (myself included) can’t look at a whole lot of numbers and instantly grasp what they mean, even if they have the context for them. That’s why people make graphs – pictures that give the overall story for people that don’t need every little detail.
Most spreadsheet programs offer multiple types of graphs. The most commonly used types are pie charts, line charts, and bar charts.
Most people have seen a pie chart. Pie charts are the round graphics that look like a circle divided into sections. They’re most commonly used to represent parts of a whole, just as a slice is part of a pie.
Anyone who has ever seen a graph of stock prices has seen a line chart. Think of the stereotypical chart with a jagged line somewhere in the middle, possibly with an arrow at the right end of the line heading either up to the top or down to the bottom. They’re best used to represent continuous values, even if all you have is snapshots.
Bar charts are a little less easy to describe. Most people have seen them in newspapers, such as in a story comparing 2010 year-end circulation to 2009, 2008, and 2007. They’re best used to represent distinct values.