The problem is that the model was fantastically far off from reality. (For whatever reason - incompetence, bad inputs, willful deception, religion - doesn't ma

The problem is that the model was fantastically far off from reality. (For whatever reason - incompetence, bad inputs, willful deception, religion - doesn't matter for this discussion.) I could construct a prediction that the high air temperature in New York tomorrow will be 80 degrees Celsius with a standard deviation of 3 degrees. Then when the observed value is actually 5 degrees, that's 25 standard deviations off from my "prediction". But it doesn't mean that the observed event was actually a 1-in-billions occurrence, that New York experienced an astronomically unlikely cold snap. It means my prediction was unrealistic and wrong, that it didn't model reality.