Add a TRIMMEAN to averages or create new transform

Feature Requests
1

  1. What is your feature/integration request?
    A trimmean function takes a list of numbers and removes a portion of that list before calculating a mean for the new list. It takes two arguments 1. An array 2. a rational number between 0 and 1. It outputs a real number.

  2. What problem would this feature/integration solve?
    It would help me with some statistical modeling and to remove numbers that fall in the 3rd and 4th standard deviations.

  3. How do you solve/workaround this problem today?
    Google sheets.