Lesson 5: corrected excerpt
A corrected version of the Figure 5.07 / 5.08 material, for temporary reference until the module is updated.
What was corrected below
With positively skewed data, most values cluster towards the lower end, and a small number of unusually high values stretch a long tail out to the right. The mode always sits at the peak. Here, that's on the left. Moving away from the peak into the tail, the mean gets pulled furthest of the three: Mode < Median < Mean.
With negatively skewed data, most values cluster towards the higher end, and a small number of unusually low values stretch a long tail out to the left. The mode again sits at the peak, here on the right. The mean is pulled furthest towards the tail on the low side: Mean < Median < Mode.
| Skew | Long tail points | Bulk of data (peak) | Order (low to high) |
|---|---|---|---|
| Positive (right) | Right | Left | Mode < Median < Mean |
| Negative (left) | Left | Right | Mean < Median < Mode |
| None (symmetric) | None | Centre | Mean = Median = Mode |