Margin for systematic errors
Confidence level 1-D errors
2-D errors
3-D errors
80%
1.28
Σ
1.79
Σ
2.16
Σ
85%
1.44
Σ
1.95
Σ
2.31
Σ
90%
1.64
Σ
2.15
Σ
2.50
Σ
95%
1.96
Σ
2.45
Σ
2.79
Σ
Σ
= SD of preparation/systematic errors