Confidence Limits For The Global Land Anomaly

  Since the yearly land probability function is different from a normal probability function the confidence limits of σ, 2σ and 3σ also have different probabilities associated with them than those used for the normal distribution.

The probabilities on the left and the right are for the normal distribution and the yearly distribution respectively. The land distribution is more likely to have monthly mean anomalies outside its 3s limits than one would expect for the normal distribution's 3σ limits.