How to describe shape of statistical distribution (positive skew, negatively skewed, symmetrical)

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Discussion about the shape of a distribution using a numerical example. Positively skewed and negatively skewed distributions are covered in this video.
Skewed distributions appear as lopsided frequency graphs, as opposed to symmetrical frequency distributions. Skewness appears when the majority of scores are on one side of the distribution.
For example, if an exam was really hard, most scores will be low, but there may be a few students who do really well. This appears a "tail" pointing to the right-hand side (positively skewed distribution). The reverse is true for an easy exam - the bulk of students do well, but there still may be students who don't do so well, and those scores will appear as a tail pointing to the left-hand side (negatively skewed distribution).