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Table 1 Power analysis

From: Family nurture intervention (FNI): methods and treatment protocol of a randomized controlled trial in the NICU

Outcome Measure

PMA

Reference Population μ(σ)

Detectable Difference |μ FN-μ SC|

Effect Size d

Total N Required

Infant

EEG [73]

Term

6.044 (.434)

0.2

.46

150

NNNS [88] *

Term

4.32 (1.73)

1.0

.58

96

HRV [22]

Term

1.77 (1.10)

0.5

.45

154

Bayley-III [69]

18 months

96.4 (14)

6.0

.41

174

Mother

Cortisol [89]

4 months

Median = 2.4

0.45

.40

186

  

(IQR: 1.6-4.1)

   

CES-D [53]

4 months

10.24(9.67)[90]

5.0

.52

120

  

19.8 (11.1)[91]

 

.45

158

  1. A power analysis was conducted to determine the sample size needed to ensure statistical power of (1-β) = .80.
  2. *Non-optimal reflexes. Illustrative of the 13 NNNS subscales. Citation for the reference population is the same as that for all Outcome Measures except CES-D. Abbreviations: Bayley-III, Bayley Scales of Infant Development, III; CES-D, Center for Epidemiological Studies Depression Scale; HRV, heart rate variability; NNNS, NICU Network Neurobehavioral Scale; PMA, post-menstrual age of the infant.