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Table 6 Sample size calculation (two-sided test with power = 0.80) to identify mean difference in H score between biopsy and radical prostatectomy specimen for the metformin and control group

From: Metformin and longevity (METAL): a window of opportunity study investigating the biological effects of metformin in localised prostate cancer

 

Mean Difference (SD)

in Metformin Group

Mean Difference (SD)

in Control Group

N needed

with α = 0.05

N needed

with α = 0.10

N needed

with α = 0.20

Scenario 1

15 (35)

0 (35)

86

38

50

Scenario 2

30 (65)

0 (65)

74

59

43

Scenario 3

20 (25)

5 (25)

44

35

26

Scenario 4

30 (50)

5 (50)

63

50

37