TRIMMEAN ( array , percent )

Description: Computes the mean of the interior of a data set by excluding a percentage of data points from the top and bottom tails of a data set. TRIMMEAN rounds the number of excluded data points down to the nearest multiple of 2. For symmetry, TRIMMEAN excludes a single value from the top and bottom of the data set.

Arguments:

Name	Type	Description
array	array, reference	The numeric values to trim and average.
percent	number	The fractional number of data points to exclude from the calculation. [Example: If percent = 0.2, 4 points are trimmed from a data set of 20 points (20x0.2): 2 from the top and 2 rom the bottom of the set. end example]

Return Type and Value: number – The mean of the interior of a data set.

However, if percen < 0 or percen > 1, #NUM! is returned.

[Example:

TRIMMEAN({4,6,2,5,7,8,9},0.2) results in 5.857142857

end example]