Dear Ignacio and Riccardo! Thank you for your help! I understand now what the problem was! The script is now:
loop 10 --progressive loop 10000 genr u = normal() genr u2 = round(u) endloop genr a = mean(u) genr b = sd(u) genr a2 = mean(u2) genr b2 =sd(u2) store xxx.gdt a b a2 b2 endloop First I put the "--progressive" to the wrong loop. The only problem is that this was a bit slow, with 10/10000 it took about 15 minutes. But as I awaited: the standard deviation of the rounded series is about 4% higher than that of the original one. Once again, if anybody knows papers about this topic, please let me know (I hardly found any). Thanks again! Daniel