Mean minus median: a quick skew check
When the two disagree a lot, a few large values are pulling the average.
Task:
Before reporting an average basket value, check whether it is being skewed. In B10 give the mean, in B11 the median, and in B12 the mean minus the median.
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 MEDIAN
0/3The same formula in the other shapes it takes at work.
- MEDIAN Function
The middle value, which the outlier cannot move.
CoreIntermediate - MEDIAN of an even number of values
With no single middle value, MEDIAN averages the middle two.
Intermediate - Mean minus median: a quick skew check
When the two disagree a lot, a few large values are pulling the average.
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 | Basket | Value |
| 2 | B1 | 32 |
| 3 | B2 | 28 |
| 4 | B3 | 41 |
| 5 | B4 | 35 |
| 6 | B5 | 30 |
| 7 | B6 | 260 |
| 8 | B7 | 38 |
| 9 | ||
| 10 | Mean | |
| 11 | Median | |
| 12 | Gap |
What this exercise teachesMay contain the answer
One basket of 260 lifts the mean to about 66 while the median stays at 35 — nearly double. Reporting 66 as "typical" would mislead anyone planning stock or staffing. A big gap between the two is the cue to report the median, or to show both.