Box-and-Whisker Plots are a descriptive way to show the distribution of values in a data set. To construct a box-and-whisker plot you need
5 points: the smallest point, the largest point, and what are known as the 1st, 2nd, and 3rd quartiles. The quartiles represent the boundary
points when you break the data set into four equal sized portions. Start by finding the median of the data set, this will be the 2nd quartile.
Then find the median of the lesser half, this value is the 1st quartile. Lastly the median of the higher half is the 3rd quartile.
Once you have the 5 points draw a horizontal line from the smallest point to the 1st quartile and another from 3rd quartile to the largest point.
These lines are the "Whiskers". Then draw a rectangle from the 1st quartile to the 3rd quartile, with a vertical divider at the 2nd quartile, this
is the "box". The beauty of this depiction is that each segment of the plot represents a quarter of the data set. If the whiskers are long, you
know the data is diverse. If the whiskers are short, the data is clumped together.