174 / 274
2
95% confidence interval for Sigma, given normal distribution
Degrees of
LCL
UCL Multiplier
Freedom Multiplier Multiplier
Ratio
1 0.446 31.910 71.52
2 0.521 6.285 12.07
3 0.566 3.729
6.58
4 0.599 2.874
4.80
5 0.624 2.453
3.93
<-- Long considered the minimum d.f. needed to estimate Sigma
6 0.644 2.202
3.42
7 0.661 2.035
3.08
<-- Rough 'knee' of the multiplier ratio curve
8 0.675 1.916
2.84
9 0.688 1.826
2.65
10 0.699 1.755
2.51
12 0.717 1.651
2.30
15 0.739 1.548
2.10
18 0.756 1.479
1.96
20 0.765 1.444
1.89
25 0.784 1.380
1.76
30 0.799 1.337
1.67
35 0.811 1.304
1.61
0
1
10
100
0
5
10
15
20
25
30
35
Degrees of Freedom
LCL Multiplier
UCL Multiplier
Multiplier Ratio
121