Table 2. Formulas and values involved in plotting the LC-CUSUM curve with an acceptable ECV failure rate of 50%.

Variable	Value
p0—unacceptable ECV failure rate	0.7
p1—acceptable ECV failure rate	0.5
α—probability of the type I error	0.05
β—probability of the type II error	0.20
P=ln (p1/p0)	-000.3365
Q=ln [(1−p0)/(1−p1)]	−0.5108
s=Q/(P+Q)	0.603
1−s	0.397
a=ln [(1−β)/α]	2.77
b=ln [(1−α)/β]	1.56
H=a/(P+Q)	−3.27

ECV, external cephalic version.