Logic puzzle statistics definition

[hxxhxx]

How are statistics defined? Most obvious:
Success + Penalty + Not_Completed = 100%.
If so, "Success" means completed without error, and
"Penalty" means completed but with at least one error.
But it could be something else. Anyone know?

[Martika14]

No clue, and I also don't know how the bell curve image relates to anything, because it's labeled "average", but the average time for a puzzle is not listed anywhere that I've ever been able to find. (The statistics list the median time, but median and average are VERY different.)