Speaking of "the public" as a single entity is about as useful as approximating a curve with a straight line - i.e. unless it's the most trivial case, it's oversimplified to the point of being doomed to failure.

The public is comprised of people with vast differences in cognitive ability, education, and scientific training. Most members of the public, even in highly educated countries, are easily fooled by a wide variety of logical fallacies, emotional manipulation, and statistical misdirection.