The Trim and Winsorize commands can be used to eliminate extreme points in a data set.

The Trim command return all points from X between lth and uth percentiles.

The Winsorize command is similar to Trim except that the extreme points in X are replaced with the values of the lth or the uth percentile (whichever is closer).

The first parameter X is the data set, given as e.g. a Vector.

The second parameter l is the lower percentile, the third parameter u is the upper percentile. Both l and u must be numeric constants between 0 and 100. A common choice for l and u is 5 and 95 respectively.

$\mathrm{with}\left(\mathrm{Statistics}\right)\:$

$A≔\mathrm{Array}\left(\left[\mathrm{seq}\left(i\,i=1..10\right)\right]\right)$

$A≔\left[\begin{array}{cccccccccc}1& 2& 3& 4& 5& 6& 7& 8& 9& 10\end{array}\right]$

$\mathrm{Trim}\left(A\,25\,75\right)$

$\left[\begin{array}{c}3\\ 4\\ 5\\ 6\\ 7\end{array}\right]$

$\mathrm{Winsorize}\left(A\,25\,75\right)$

$\left[\begin{array}{cccccccccc}3& 3& 3& 4& 5& 6& 7& 8& 8& 8\end{array}\right]$