Definition
Outlier
A data value noticeably far from the overall pattern of the other values.
Continue from this idea into connected AXIO math.
Spot the value far from the crowd—then investigate.
Boundary: The greatest or least value is not automatically an outlier. It must be unusually far from the pattern under the context or rule being used.
What it means
Most values may form a cluster while one value sits well away from them. That distant value may be an outlier, but the data’s context matters. Check how the value was collected and what rule is being used before deciding what it means or whether it belongs.
Remember it
Spot the value far from the crowd—then investigate.
Example
Five children take 9, 10, 10, 11, and 45 minutes on the same short puzzle. The 45-minute result is a likely outlier because it is far from the cluster from 9 to 11 minutes. It could be genuine, or it could come from an interruption or recording error.
Watch for
The greatest or least value is not automatically an outlier. It must be unusually far from the pattern under the context or rule being used.
Common mix-up
Outlier does not mean “mistake.” An outlier can be correct and important, so investigate before changing or removing it.
Exact meaning
An outlier is an observation that lies unusually far from the overall pattern of a data set, according to the context or a stated rule. It may be genuine, an error, or important evidence and should not be removed automatically.