### TRIMMEAN(array, percent)

Returns the mean of the interior of a data set.

 array The array or range of values to trim and average. percent The fractional number of data points to exclude from the calculation.

#### Remarks

 * This function 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, This function excludes a single value from the top and bottom of the data set.* This function 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, then #NUM! is returned.* If "percent" > 1, then #NUM! is returned.* 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.* For the Microsoft documentation refer to support.microsoft.com

 A 1 =TRIMMEAN({4,5,6,7,2,3,4,5,1,2,3},0.2) = 3.778