# WorksheetFunction.TrimMean (Excel)

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.

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.

TrimMean (Arg1, Arg2)

``````
Dim dblArg2 As Double: dblArg2 =
Dim dblTrimMean As Double
dblTrimMean = WorksheetFunction.TrimMean(Arg1:=, Arg2:=dblArg2)
``````

## Arguments

Arg1, Arg2

Arg1 - Array - the array or range of values to trim and average

Arg2 (Double) - 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.