Skip to main content

Table 2 Power calculation for changes in practice for various assumptions of % with practice pre-intervention – p1(20–60%), p2 (30–90%), assuming 80% power at 5% level of statistical significance (2-sided test), for sizes of effect ≤ 2 and assuming no clustering (ie ICC = 0.00)

From: The BLISS cluster randomised controlled trial of the effect of 'active dissemination of information' on standards of care for premature babies in England (BEADI) study protocol [ISRCTN89683698]

Total number of babies needed

p 1

P 2

 

30

35

40

45

50

55

60

65

70

75

80

85

90

 

60

        

712

304

162

98

62

 

55

       

752

324

176

108

70

48

 

50

      

774

338

186

116

76

54

38

 

45

     

782

346

192

120

82

58

42

32

 

40

    

774

346

194

122

84

60

44

   

35

   

752

388

192

122

84

62

     

30

  

712

324

186

120

84

       

25

 

656

304

176

116

         

20

546

276

162

          Â