Skewness

This is a measure of asymmetry about its mean.
The skewness of a distribution can be positive, negative or undefined
If more values are clustered either above or below the mean the distribution is said to be skewed
When numbers are not spread evenly around a central value.
When more values fall below the mean the distribution is positively skewed
When more values fall above the mean the distribution is negatibely skewed.

Calculating the size of the skew will help to identify any bias in the data.
SKEW

Positive Skew

There is a long trail at the positive end of the distribution
stats book - pg 21 examples

order is: mode, median, mean

Negative Skew

order is: mean. Median, mode

Undefined Skew