# Table 4 Mixture Modeling Results for White Singleton Infants

Quantity p1 p2 p3 p4
$\stackrel{\wedge }{\theta }$ [average of 25 estimates] .005 .117 .810 .068
${\stackrel{\wedge }{S}}_{\theta }$ [standard deviation of 25 estimates] .001 .010 .012 .006
${\stackrel{\wedge }{B}}_{\theta }$ [bias adjustment] .001 .012 .011 .007
Confidence interval (.004, .006) (.099, .135) (.792, .827) (.058, .078)
Quantity μ1 μ2 μ3 μ4
$\stackrel{\wedge }{\theta }$ [average of 25 estimates] 862 2948 3402 4056
${\stackrel{\wedge }{S}}_{\theta }$ [standard deviation of 25 estimates] 60 52 6 18
${\stackrel{\wedge }{B}}_{\theta }$ [bias adjustment] 22 47 4 36
Confidence interval (809, 915) (2874, 3021) (3395, 3410) (4011, 4100)
Quantity σ1 σ2 σ3 σ4
$\stackrel{\wedge }{\theta }$ [average of 25 estimates] 233 776 421 416
${\stackrel{\wedge }{S}}_{\theta }$ [standard deviation of 25 estimates] 40 23 5 19
${\stackrel{\wedge }{B}}_{\theta }$ [bias adjustment] 42 25 5 11
Confidence interval (170, 295) (739, 813) (413, 429) (395, 437)
1. Parameters in a 4-component normal mixture model for birthweight distribution are estimated, based on 25 samples of size 50,000 from the population of white singletons in general. Confidence intervals are constructed using Equations (6) and (7) with C 0 = 2.5 and φ = .0055.