What is TRIMMEAN function in Excel?
TRIMMEAN function is one of Statistical functions in Microsoft Excel that returns the mean of the interior of a data set. TRIMMEAN calculates the mean taken by excluding a percentage of data points from the top and bottom tails of a data set. You can use this function when you wish to exclude outlying data from your analysis.
Syntax of TRIMMEAN function
TRIMMEAN(array, percent)
The TRIMMEAN function syntax has the following arguments:
- Array: The array or range of values to trim and average.
- Percent: The fractional number of data points to exclude from the calculation. For example, if percent = 0.2, 4 points are trimmed from a data set of 20 points (20 x 0.2): 2 from the top and 2 from the bottom of the set.
Explanation of TRIMMEAN function
- If percent < 0 or percent > 1, TRIMMEAN returns the #NUM! error value.
- TRIMMEAN rounds the number of excluded data points down to the nearest multiple of 2. If percent = 0.1, 10 percent of 30 data points equals 3 points. For symmetry, TRIMMEAN excludes a single value from the top and bottom of the data set.
Example of TRIMMEAN function
Steps to follow:
1. Open a new Excel worksheet.
2. Copy data in the following table below and paste it in cell A1
Note: For formulas to show results, select them, press F2 key on your keyboard and then press Enter.
You can adjust the column widths to see all the data, if need be.
| Data | ||
| 4 | ||
| 5 | ||
| 6 | ||
| 7 | ||
| 2 | ||
| 3 | ||
| 4 | ||
| 5 | ||
| 1 | ||
| 2 | ||
| 3 | ||
| Formula | Description | Result |
| =TRIMMEAN(A2:A12,0.2) | Mean of the interior of the data set contained in A2:A12, with 20 percent excluded from calculation. | 3.778 |