Boxplots

A graphical summary of a distribution's shape, central tendency and spread. It's like a bird's-eye view (looking down from the top) of a distribution. Their strong advantage is in visually comparing multiple distributions and statistical characteristics along the same scale.
Related StatStuff Video: 
   -Section 6-Analyze Phase, Lesson #18 - Hypothesis Testing: Central Tendency – Normal (Compare 2+ Factors)