NOAA / Space Weather Prediction Center

Observed Fredericksburg A index Plot

 

Box plots of the annual distribution of daily geomagnetic A index observed at Fredericksburg, VA from 1986 through 2013. Stars indicate the minimum and maximum values observed in the year, the small square indicates the mean observed value, and the horizontal line within the box indicates the median. The box contains the observed values from the lower quartile (25%) to the upper quartile (75%) of the distribution and includes 50% of the observed values. The box “whiskers” encompass 98% of the observed values (1% to 99% of the distribution).

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