ZScore
Flags unusual values in a column by scoring each one on how far it sits from the column's typical level. A score near 0 is ordinary; beyond +2 or -2 is unusual; beyond +3 or -3 is extreme. It is a quick way to surface the handful of rows worth a second look in thousands of transactions.
Inputs
| Input | Accepts | Required |
|---|---|---|
Series | Series (a list of numbers) | Yes |
Outputs
| Output | Produces |
|---|---|
Result | Series (a list of numbers) |
Example
Your Payments table has 5,000 rows with an Amount column that mostly runs
$500 to $3,000. Score the column and almost every payment lands between -1 and
1, but a $48,000 wire scores 3.4. That single number tells you it is far
outside the normal pattern and worth reviewing, without you having to sort and
scan the whole table.
Tips
The scores come back in the same row order as the input, so you can write them next to the original amounts and sort or filter on the score column to pull the exceptions to the top.