If all you care about is the mean, I think it was Applied Cryptography that suggested: 1. First person picks a random number and adds it to their salary. Write

If all you care about is the mean, I think it was Applied Cryptography that suggested: 1. First person picks a random number and adds it to their salary. Writes it down ands hands it to the next person. 2. Next person adds their salary to that number and writes it down on a new note, hands to the next person. 3. When the first person gets the note, subtract the original number and divide by number of people.