Table 1 

Power analysis 

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 
BayleyIII [69] 
18 months 
96.4 (14) 
6.0 
.41 
174 
Mother 

Cortisol [89] 
4 months 
Median = 2.4 
0.45 
.40 
186 
(IQR: 1.64.1) 

CESD [53] 
4 months 
10.24(9.67)[90] 
5.0 
.52 
120 
19.8 (11.1)[91] 
.45 
158 



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

Welch et al. BMC Pediatrics 2012 12:14 doi:10.1186/147124311214 