I'm looking for datasets in which any quantity is estimated by an individual person. These are datasets in the tradition of Galton (1907), in which individuals estimated the weight of an ox.
Ideally the individual persons would be making these estimates without consultation with other individuals or resources, but this is not essential.
I need to know the true value for the estimate.
Galton, F. (1907). Vox populi (the wisdom of crowds). Nature, 75, 450-451.