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Table 4 Number of consecutive and total cases required to cross the lower limit line for different combinations of acceptable (p0) and unacceptable (p1) failure rates, type 1 error (α) and type 2 error (β).

From: Sentinel lymph node biopsy for breast cancer using methylene blue dye manifests a short learning curve among experienced surgeons: a prospective tabular cumulative sum (CUSUM) analysis

Total no. cases, assuming 3 failures

No. consecutive cases, assuming no failures

p0/p1

α/β

97

55

0.05/0.1

0.05/0.05

84

42

"

0.05/0.1

46

29

"

0.05/0.2

49

27

0.1/0.2

0.05/0.05

43

21

"

0.05/0.1

36

13

"

0.05/0.2

29

15

0.15/0.3

0.05/0.05

27

12

"

0.05/0.1

22

8

"

0.05/0.2