In this context, "99% certainty" refers to a specific prediction interval, not "a guess I'm pretty confident in," like it would in colloquial speech. http://en

In this context, "99% certainty" refers to a specific prediction interval, not "a guess I'm pretty confident in," like it would in colloquial speech. http://en.wikipedia.org/wiki/Prediction_interval http://en.wikipedia.org/wiki/Prediction_interval may help.