Determining skewness

What you need to know

Determine the skewness direction of a given data distribution through visual inspection and formal calculation.
Calculate the skewness formally using the formula:

$\text{Skew} = \frac{3(\text{mean} - \text{median})}{\text{standard deviation}}$

standard deviation

3(mean−median)

Understand that positive skew often dictates that the mean is greater than the median, which in turn is greater than the mode.
Evaluate skewness by comparing quartile spreads, indicating positive skew when the difference between the median and lower quartile is less than the difference between the upper quartile and the median.