Solved. Thanks. ────────────────────────────────────────────────────────────────── De: "Svein Erling Tysvær setysvar@... [firebird-support]" Enviada: 2016/12/01 08:18:14 Para: firebird-support@yahoogroups.com Assunto: Re: [firebird-support] Basics of Statistics - Mathematics: Mean (Average), Median, Mode and Range ? Don't know whether Firebird has internal functions for this or not and it is likely that there are more elegant solutions available, but the below queries should be ways to get what you ask (although I don't know whether you want to return all values for mode and whether or not you want the average in case of two median values). execute block returns (mode integer) as declare variable occurences integer; declare variable dummy integer; begin select , count(*) from group by 1 order by 2 desc rows 1 into :dummy, :occurences; for select from group by 1 having count(*) = :occurences into :mode do suspend; end execute block returns (median decimal(9, 1)) as declare variable occurences integer; declare variable RowsFrom integer; declare variable RowsTo integer; begin select count(*) from into :occurences; RowsFrom = ((:occurences-1)/2)+1; RowsTo = (:Occurences/2)+1; with tmp(tmp) as (select cast( as decimal(9, 1)) from rows :RowsFrom to :RowsTo) select sum(tmp)/(:RowsTo-:RowsFrom+1) from tmp into :Median; suspend; end select max()-min() as Range from HTH, Set