STDEV Function
The same spread as VAR, back in units you can read.
Task:
The same five lead times. Put their standard deviation in B7 — this time the answer comes back in days.
Interactive Spreadsheet
Hints
+5 XPno-hints bonusSolve it on your own to keep the bonus. Each hint gets one step closer to the formula.
Variations of STDEV, VAR
0/3The same formula in the other shapes it takes at work.
- STDEV Function
The same spread as VAR, back in units you can read.
CoreAdvanced - Coefficient of variation: spread relative to size
STDEV divided by AVERAGE lets you compare things measured on different scales.
Advanced - Flag values more than two standard deviations out
A simple, defensible outlier rule built from AVERAGE and STDEV.
Advanced
The data in this exercise
This is the grid you start with. Cell references in the task — B6, C2 — point at the row numbers and column letters below.
| A | B | |
|---|---|---|
| 1 | Month | Lead time (days) |
| 2 | January | 9 |
| 3 | February | 14 |
| 4 | March | 7 |
| 5 | April | 16 |
| 6 | May | 4 |
| 7 | Standard deviation |
Functions used here
What this exercise teachesMay contain the answer
The variance was 24.5 days-squared; the standard deviation is its square root, about 4.95 days. That is a number you can put in a sentence: lead times average 10 days, give or take about 5. For data that clusters around its mean, roughly two thirds of values fall within one standard deviation of it, so this is realistically a 5-to-15 day supplier — a very different thing to promise a customer than 10.