# Talk:Documentation/Calc Functions/TRIMMEAN

(1) Summary. Suggest the following alternative – “Calculates the mean of a data set ignoring a percentage of the values at the margins.”.
(2) Returns. Suggest replacing “Data without the Alpha percent of data at the margins” with “ignoring a specified percentage of data at the margins.”.
(3) Arguments. Insert “or” before “equal”.
(4) Arguments, general. I expect that there are other error conditions to consider. For example, what happens if cells in Data contain anything other than real numbers? What happens if Data contains no values? What happens if alpha is passed as a cell reference and the cell does not contain a real number?
(5) Arguments, alpha. Please explain how given alpha, the function decides how many values to ignore at each end. Alpha may not immediately imply an even number of points exactly. In fact, we need to state that the same number of points are dropped at each end.
(5) Additional details, last line. Insert “the” before “ith”.
(6) Additional details, general. Would it be worth mentioning that TRIMMEAN(data, 0) = AVERAGE(data)?
(7) Examples, both. Suggest relacing “the 10 percent of the values representing the highest values and the 10 percent of the values representing the lowest ones” with the more straightforward “the lowest 10% of values and the highest 10% of values” (with the obvious change to 25% for the 2nd example). Also, I do not understand what “The percentage numbers refer to the amount of the untrimmed mean value, not to the number of summands” means.

--Stevefanning (talk) 2020-11-08T13:43:18 (UTC)