How values are spread.
WHAT A DISTRIBUTION IS
How values are spread across a range.
WHY IT MATTERS
Two sets of records with the same average can be completely different.
WHAT TO LOOK AT
The lowest and highest values Where most values sit Whether a few extremes pull the average
HOW TO SEE IT
Sort the values, or chart them in bands.
WHAT COMMON SHAPES TELL YOU
- Values clustered near the middle: typical experience matches the average
- Values spread widely: the average describes nobody
- A long tail of large values: a few records dominate
THAT LAST SHAPE
Extremely common in business: customers, orders, products.
WHAT IT MEANS
A small proportion accounts for most of the total.
WHAT TO DO ABOUT THAT
Identify which, and treat them accordingly.
WHAT TO REPORT
Median alongside average, where the spread is wide.
WHAT TO AVOID
Describing typical experience with an average that no record resembles.
