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. Author manuscript; available in PMC: 2015 Mar 9.
Published in final edited form as: J Biopharm Stat. 2014;24(3):634–648. doi: 10.1080/10543406.2014.888444

Table 4.

Monte Carlo results (based on 500 replicates): Linear regression with missing covariate where N = 200, X1 ~ Poisson(1), X2 ~ N(3 − 0.5 * X1, 0.5), Y ~ N(b0 + b1 * X1 + b2 * X2, 8), missing rate = 0.40, Spearman correlation coefficient between X1 and X2: −0.68, Spearman correlation coefficient between X1 and Y: 0.23, and Spearman correlation coefficient between X2 and Y: −0.22

b0 = 10.000
 b1 = 1.333
 b2 = −1.333
Method Esta SDb SEc CRd Est SD SE CR Est SD SE CR
FO 10.128 3.451 3.505 95.8 1.304 0.786 0.806 97.0 −1.364 1.116 1.137 94.6
CC 11.604 3.282 3.311 92.4 0.786 0.748 0.739 87.8 0.151 1.065 1.098 71.0
IPWDR12 11.686 4.694 4.821 94.4 0.864 1.272 1.161 90.8 −1.786 1.438 1.529 94.6
IPWDR21 8.457 5.195 5.253 94.0 1.756 1.401 1.415 90.6 −0.835 1.592 1.611 93.8
IPWDR22 9.248 6.337 6.451 92.8 1.529 1.720 1.846 91.0 −1.043 1.921 2.064 94.0
NNMIB12 M1: misspecified; M2: correctly specified
(3,0.8,0.2)e 11.162 4.671 4.972 95.0 1.040 1.254 1.300 94.0 −1.636 1.432 1.522 94.8
(3,0.5,0.5) 10.781 5.102 5.283 94.8 1.167 1.421 1.423 93.4 −1.517 1.542 1.601 94.6
(3,0.2,0.8) 10.599 5.490 5.642 94.2 1.246 1.592 1.582 92.6 −1.452 1.637 1.685 93.8
(5,0.8,0.2) 11.294 4.350 4.808 96.6 1.001 1.134 1.255 96.6 −1.681 1.350 1.474 95.6
(5,0.5,0.5) 10.922 4.773 5.046 94.6 1.131 1.300 1.356 94.8 −1.569 1.460 1.534 94.8
(5,0.2,0.8) 10.777 4.971 5.209 94.6 1.205 1.426 1.456 93.6 −1.522 1.497 1.566 94.4
NNMIB21 M1: misspecified; M2: misspecified
(3,0.8,0.2) 10.634 4.840 4.382 92.2 1.187 1.275 1.105 92.2 −1.493 1.484 1.369 94.0
(3,0.5,0.5) 11.144 4.504 4.421 93.8 1.036 1.152 1.115 92.4 −1.643 1.395 1.378 93.8
(3,0.2,0.8) 11.674 4.011 4.391 95.8 0.879 0.979 1.102 95.0 −1.799 1.264 1.366 95.2
(5,0.8,0.2) 10.725 4.738 4.345 94.0 1.165 1.235 1.096 90.6 −1.523 1.456 1.357 94.4
(5,0.5,0.5) 11.209 4.299 4.368 94.8 1.018 1.088 1.100 93.4 −1.665 1.335 1.361 95.0
(5,0.2,0.8) 11.830 3.824 4.339 95.0 0.833 0.924 1.089 95.4 −1.847 1.212 1.349 95.0
NNMIB22 M1: misspecified; M2: correctly specified
(3,0.8,0.2) 10.047 5.358 4.785 91.2 1.375 1.475 1.244 88.2 −1.311 1.625 1.481 92.2
(3,0.5,0.5) 10.015 5.546 5.165 92.2 1.401 1.564 1.388 89.8 −1.295 1.668 1.577 92.2
(3,0.2,0.8) 10.184 5.653 5.624 93.0 1.377 1.648 1.579 89.8 −1.332 1.684 1.686 93.0
(5,0.8,0.2) 10.192 5.190 4.674 93.0 1.337 1.407 1.217 91.8 −1.360 1.578 1.446 92.8
(5,0.5,0.5) 10.174 5.272 4.909 92.6 1.361 1.471 1.316 90.8 −1.350 1.596 1.504 93.4
(5,0.2,0.8) 10.368 5.227 5.154 92.8 1.337 1.510 1.442 91.8 −1.406 1.569 1.554 92.8
a

Average of 500 point estimates.

b

Empirical standard deviation of 500 point estimates.

c

Average of 500 estimated standard errors.

d

Coverage rate of 500, 95% confidence intervals.

e

(NN, w1, w2).