how to select a statistical range in an excel

Question

I have a large array of numbers. These readings were taken every day for four months. One gadget is represented by each row. I must determine the trendline and disregard the outliers. I made an effort to determine the IQR, then the range, and finally a filter to remove outliers that fall beyond the range. the problem is that there are a lot of repetitive results so the q1 and the q3 could very easily be the same number. is there a way to select the central 90% of results in a range? let's say from  [1,1,1,1,1,1,1,1,2,3,4,5,7,8,9,9,9,9,9,9] Select [1,1,1,1,1,1,1,2,3,4,5,7,8,9,9,9,9,9] to make life harder, I'd also like to be able to select the associated date with the day the measurement was taken. the dates are in a separate row.

Answer 1

The lowest 5% and top 5% will not be included in the dynamic array that this formula returns. Your data range is assumed to be A1–A20.

=FILTER($A$1:$A$20,(ROW($A$1:$A$20)>0.05*COUNT($A$1:$A$20))*ROW($A$1:$A$20)<0.95*COUNT($A$1:$A$20))