discard hi, low then avg

I would like to obtain an English like algorithm that I can convert to Informix code in either the extensions section of a Perform screen or in 4gl code. Problem: There are 5 judges and each submits one score for each candidate. The candidate's average score is computed averaging 3 remaining judges' scores after: Discarding the lowest score or the 1st blank if there is one. Discarding the highest score or the 2nd blank if there is one. Should 3 or more of the judges fail to submit a score I don't know whether to divide the sum of the scores received by 3 or divide the sum of the scores received by the number of scores received. A lot of athletic events (gymnastics, ice skating, etc) use this type of scoring but I don't know whether they allow blank scores (where for some reason a judge refuses to give a score). In our case I'm assuming it could happen. Is this an actual statistical/mathematical formula? ~