I filter out any data points <5 seconds (as seen in the graph), so completing your attempt in under 5 seconds should do it.
Ideally, people would do the challenge first and then see where they lie on the graph before seeing the data itself.
that's what I ended up doing. I was looking at it, clicked to see your other projects, and then went back and couldn't view the results
Nice bell curve around 60s but a little higher on left than right (more people underestimate, but proportionally) and there’s a spike at 0-8 seconds (from people who just wanted to see results or decided to quit quickly.)
I think there's also a good amount of people who didn't get what the site was actually asking the user to do and just did what was prompted.