In mid-June through early July, participants on the Arctic Sea Ice (ASI) blog posted 82 individual predictions for the mean NSIDC September Arctic sea ice extent. The median value of these 82 predictions was 3.2 million km2, with an interquartile range (approximately the middle 50% of predictions) from 2.7 to 3.9 million km2.
Medians and quartiles are employed as basic summaries here because they offer high resistance to outliers, are easy for anyone to replicate, and map into more detailed analysis using graphics or quantile regression. Individual predictions ranged from 0 to 5.6 million km2. A stem-and-leaf display compactly shows the distribution: