No, evidence indicates that this is true of some things in some situations and untrue of other things in other situations. It depends on the type of question, the type of available information, the individuals being compared, the group being compared etc.
No, that's nonsense. You're confusing the view that democracy is the best available way to make these decisions with the assumption that the decisions thus made are guaranteed to be "best" because they are "wise". Not so. Democracy is also the best way to let people make poor and unwise decisions for their society.Democracy is not the same thing no, democracy is letting the people decide and the people make the best choices because they are wise.