Average Excluding Outliers

[#1]

I have a very basic function calculating the average. 

Avg ([Dictation Time])

The issue is I want to throw out the top 5% highest values.
For instance if I had :

12

15

18

19

106

17

54

89

20

87

78

65

98

15

63

32

65

89

899

999

We would discard 899 and 999 as outliers and calculate the average
of the remaining items. Any thoughts on how to do this?

[Nicole-Smith]

avg({<[Dictation Time]={'<$(=max([Dictation Time], $(=count({1}Data)*.05)))'}>}[Dictation Time])

[#3]

Thanks, I just this but it is only removing teh TOP value rather than the TOP 5%.

[Gysbert_Wassenaar]

There are 20 values, so the top 5% values is only 999, not 899 and 999. Those would be the top 10% values.

You can create a variable, e.g. vCutOff, as =max([Dictation Time],- ceil(count([Dictation Time])*0.05))

Then the expression to calculate the average is =avg({<[Dictation Time]={'<$(vCutOff)'}>}[Dictation Time]).