If somebody asked you "how did that group do?" and you could only give them one number to describe the whole group, what number would you pick? Would you pick the biggest? The middle one? Something in between?

Here are three dot plots. Every dot is one person's score, sitting above its value on the line. Watch how the mean and median lines sit in each picture, sometimes together and sometimes a little apart.

For each one we will line the dots up on the plot, then find the mean, the median, the mode and the range. The last set has a high value at the end, so we will look once more at where the mean and the median land, and predict which one is further out.