Hi,
if it is to be "readonly", why do you show it at all (as jelo)?
Here you only define some age brackets.
And if you really want to show his age bracket to the respondent, do it in a question of type "text display".
Two more things:
in Question validation equation: S2=if(S1.NAOK < 20, "1", if(S1.NAOK >= 20 && S1.NAOK <= 25, "2", if(S1.NAOK >= 26 && S1.NAOK <= 30, "3", if(S1.NAOK >= 31 && S1.NAOK <= 35, "4", if(S1.NAOK >= 36, "5"))))))
1. in Question validation equation? Usually you do this in a question of type "equation"
2. You do not understand the logic of the IF function quite well.
You see, all your ">=" parts are not necessary; because they are always TRUE; otherwise these parts were not reached.
S2=if(S1.NAOK < 20, "1", if(S1.NAOK <= 25, "2", if(S1.NAOK <= 30, "3", if(S1.NAOK <= 35, "4", "5")))) is sufficient.
Joffm