Scatter Plot Explorer

Pre-Algebra · Axiom Academy

Two measurements on the same person become one dot. Plot enough of them and a hidden pattern walks right out of the data. When you measure two things about the same person, you get a pair Suppose you record both the height and the shoe size of four people. Each person gives you two numbers that belong together — a pair . Read down a list and the numbers just sit there. But pin each pair to a graph and a relationship you couldn't see in the list suddenly appears. Watch each pair lift off the table and land at its spot on the graph: height runs left-to-right, shoe size runs bottom-to-top. One dot per person — and once all four are down, look at where they sit. A scatter plot turns a list of pairs into a picture — and the picture is where patterns live. An upward pattern: the line of best fit Here are seven people, height versus shoe size. The dots clearly climb to the right — taller people tend to have bigger feet. Drag the slope until a single straight line threads the cloud as tightly as possible; the total miss readout shrinks as the line fits better, and the gap between line and dots is smallest right at the line of best fit . A line that rises to the right is the signature of a positive association : as one variable goes up, so does the other. Up, flat, or down — the shape tells the story

This is the written version of the interactive lesson above. See the full Pre-Algebra course.