I learned how to use color tiles to show box and whisker structure at a recent grade level meeting. The instructor said to get 7 tiles (or you could use 11) and line them up. Tell the students to pull the middle tile to the top. This is the median or middle of the box. Then you have two groups left. Pull the median of each group to the top. The one from the left group is named the lower quartile. The median from the right side is named the upper quartile. This makes the outside of your box. The farthest tiles to the left and right are the outliers and they are the lower extremes which will be connected to the box creating whiskers.
After this we worked some example test prep problems. They had a much better understanding of the objective and I did too! :)