PERCENTILE(array,k)
PERCENTILE 100*@k- ( x , @k x).
@array @k < 0 @k > 1, PERCENTILE #NUM!.
Excel.
, A1, A2, ... A5 11.4, 17.3, 21.3, 25.9 40.1.
PERCENTILE(A1:A5,0.42) 20.02.
QUARTILE.