A skewed distribution is one where frequency data is not spread evenly (i.e. normally distributed); the data is clustered at one end. Data that is positively skewed has a long tail that extends to the right. Data that is negatively skewed have a long tail that extends to the left. As a general rule, when data is skewed to the right (positively skewed), the mean will be greater than the median and when data is skewed to the left (negatively skewed), the median will typically be greater than the mean.