Purpose
Return value
Syntax
=TRIMMEAN(array,percent)- array - Values to trim and average.
- percent - The number of data points to exclude from the calculation.
Using the TRIMMEAN function
The Excel TRIMMEAN function calculates mean (average) while excluding outliers. The number of data points to exclude is provided as a percentage.
TRIMMEAN works by first excluding values from the top and bottom of a data set, then calculating mean. The number of data points is provided as a percentage. The percentage can be input either in decimal format or percent format:
=TRIMMEAN(A1:A100,0.1) // exclude 10%
=TRIMMEAN(A1:A100,10%) // exclude 10%
=TRIMMEAN(A1:A100,0.2) // exclude 20%
=TRIMMEAN(A1:A100,20%) // exclude 20%
It's important to note that TRIMMEAN rounds excluded data points down to the nearest multiple of 2. For example, with 50 data points, 10% equals 5 values. In this case, TRIMMEAN will round 5 down to 4, then exclude two values from the top, of the data set, and two values from the bottom of the data set.
Related functions
AVERAGE Function
The Excel AVERAGE function calculates the average (arithmetic mean) of supplied numbers. AVERAGE can handle up to 255 individual arguments, which can include numbers, cell references, ranges, arrays, and constants.
AVERAGEIF Function
The Excel AVERAGEIF function calculates the average of numbers in a range that meet supplied criteria. AVERAGEIF criteria can include logical operators (>,<,<>,=) and wildcards (*,?) for partial matching.
MODE Function
The Excel MODE function returns the most frequently occurring number in a numeric data set. For example, =MODE(1,2,4,4,5,5,5,6) returns 5.
