Statistical assignment in colour numeric sets

The 12 ranges created when the STATISTICAL option is used are:

• MEAN – 3s    » 0.01% of distributed data
• MEAN – 2s    » 2.5% of distributed data
• MEAN – 1.645s    » 5% of distributed data
• MEAN – 1.3s    » 9.5% of distributed data
• MEAN – 1s    » 16% of distributed data
• MEAN – 0.7s    » 25% of distributed data
• MEAN 50% of distributed data
• MEAN + 0.7s    » 75% of distributed data
• MEAN + 1s    » 84% of distributed data
• MEAN + 1.3s    » 90.5% of distributed data
• MEAN + 1.645s    » 95% of distributed data
• MEAN + 2s    » 97.5% of distributed data
• MEAN + 3s    » 99.9% of distributed data