Skip to main content
. Author manuscript; available in PMC: 2014 Mar 1.
Published in final edited form as: Environmetrics. 2012 Dec 20;24(2):132–142. doi: 10.1002/env.2193

Table 3.

Bias, coverage, average width of 95% confidence interval (CI), and means square error (MSE) for the regression coefficient estimate for x under the correct assumption that the underlying distribution for x is bivariate normal

Simple substitution of LOD Distribution-based MI Bayesian MI

sample size % <LOD (x1, x2) bias CI coverage CI width bias CI coverage CI width bias CI coverage CI width MSEs MSEs/MSEd MSEs/MSEb
50 (10,20) 0.0157 94.42 0.88 0.0021 95.10 0.80 0.0004 95.34 0.79 0.06 1.32 1.37
(20,30) 0.0227 94.62 0.97 −0.0031 96.34 0.82 −0.0057 96.42 0.81 0.07 1.66 1.76
(30,40) 0.0327 94.32 1.08 −0.0079 97.42 0.85 −0.0118 97.62 0.83 0.09 2.17 2.38
(40,50) 0.0457 94.12 1.23 −0.0144 98.20 0.89 −0.0203 98.40 0.85 0.12 3.01 3.46
(50,60) 0.0624 94.00 1.43 −0.0204 99.00 0.93 −0.0272 98.98 0.87 0.16 4.43 5.31
(60,70) 0.0905 93.76 1.73 .* . * . * −0.0362 99.34 0.89 0.27 . * 9.72
200 (10,20) 0.0140 94.80 0.44 0.0004 95.60 0.39 −0.0002 95.48 0.39 0.01 1.35 1.36
(20,30) 0.0218 94.64 0.48 −0.0032 96.34 0.40 −0.0043 96.52 0.40 0.02 1.69 1.73
(30,40) 0.0304 94.54 0.54 −0.0078 97.10 0.41 −0.0093 97.24 0.41 0.02 2.22 2.27
(40,50) 0.0405 94.38 0.60 −0.0140 97.86 0.43 −0.0153 97.58 0.43 0.03 2.96 3.08
(50,60) 0.0523 94.12 0.70 −0.0216 98.02 0.45 −0.0234 98.02 0.44 0.04 4.07 4.22
(60,70) 0.0673 94.18 0.83 −0.0307 98.62 0.47 −0.0335 98.66 0.46 0.05 6.15 6.43

Note: The true regression coefficient for x is 0.1. MSEs is the MSE for the estimate based on simple substitution of LOD; MSEs/MSEd is the relative efficiency of distribution-based MI and simple substitution methods; MSEs/MSEb is the relative efficiency of Bayesian MI and simple substitution methods. The correct underlying distributional assumption for x is bivariate normal.

*

The results are not presented due to convergence problems in the estimation process when sample size is small and the degree of left-censoring is high.