Here's an Algebra brainstorming opportunity... anyone got an answer?

How can matrices be used in your real life? How are they applicable? Let's take a look at how your friends spend their time in an average day. Make a 4x4 matrix. Label the top 4 boxes "School," "Extra-Curricular," "Home work," and "TV/Video Games." Along the side, list yourself and 3 friends. Poll your friends and fill out the table, rounding the time to whole numbers. Compare this matrix to the matrices you have been doing. What do you notice? Why are matrices useful?