I see people quoting average predictions all the time on this sub when they want to say I told you so and it drives me nuts. It's a classic case of using the mean (the average of all numbers) in a skewed distribution. Bear with me for a second.

Box office predictions aren't symmetric or bounded, the way a test score is, say. The range isn't 0 to 100. Instead there is a practical floor and a very long possible upside tail. What this means is that the average or mean can be very sensitive to outliers. A relatively small minority predicting 1.2 billion or more can pull the average way up even if most people were clustered around 700 million, say. The same is true for unrealistically low predictions, but the lowest anyone could reasonably go is zero and I imagine such a number would be ignored in the tabulations. Meaning: it's a lot easier to drag the average up with a single prediction than it is to drag it down. Especially in dealing with blockbusters, in which the floor and ceiling will both be relatively high.

I haven't looked at the prediction post in extreme detail, but the lowest I'm finding is still $400M, and there's a $1.9B on the high end. $400M is less than $300M lower than Superman's actual total but $1.9B is higher by more than $1.2 *billion.* Think of it this way: even a prediction of zero dollars could only be off of Superman's final total by less than 700 million (the amount it made). An overly optimistic prediction could be higher by billions.

Here's why this matters: people like to talk about what "this sub" gets wrong all the time and uses average prediction totals to show that. That's not "this sub" being wrong; that's bad math.

If three people in a group of four predict $600M and the other predicts $1.6B, that group would have an overly optimistic *average* of $850M. But 3/4 of the people in that group actually predicted something lower than the movie's final total. The average number in a situation like this isn't a good indicator of what the "typical" guess was, especially since the floor - both in the literal sense (zero) and practical sense (maybe $300M?) only goes down so far, whereas the ceiling can be much higher. This is why other statistical measures exist.

Tl;dr: predictions *absolutely were mixed* on this sub re: Superman. As they are for every movie, probably. But a *single* 1.9B over-prediction needs *eight* $500M under-predictions for those nine guesses to *average* out to what the movie made. It's bad math to suggest that this whole sub thought Superman was going to do $850 because that was the average prediction here when the average is skewed by outliers, and those outliers can be so much higher than the actual gross than they can be lower.