| Multiple Imputation of Missing Blood Lead Levels using MCMC Method |
| Treatment of Lead Exposed Children (TLC) Trial |
| Model Information | |
|---|---|
| Data Set | WORK.TLC |
| Method | MCMC |
| Multiple Imputation Chain | Single Chain |
| Initial Estimates for MCMC | EM Posterior Mode |
| Start | Starting Value |
| Prior | Jeffreys |
| Number of Imputations | 50 |
| Number of Burn-in Iterations | 5000 |
| Number of Iterations | 500 |
| Seed for random number generator | 57313131 |
| Missing Data Patterns | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Group | trt | y1 | y2 | y3 | y4 | Freq | Percent | Group Means | ||||
| trt | y1 | y2 | y3 | y4 | ||||||||
| 1 | X | X | X | X | X | 60 | 60.00 | 0.300000 | 25.813333 | 21.040000 | 21.153333 | 22.698333 |
| 2 | X | X | X | X | . | 14 | 14.00 | 0.857143 | 27.857143 | 15.471429 | 16.257143 | . |
| 3 | X | X | X | . | X | 8 | 8.00 | 0.625000 | 25.150000 | 16.450000 | . | 19.650000 |
| 4 | X | X | X | . | . | 6 | 6.00 | 1.000000 | 29.300000 | 15.150000 | . | . |
| 5 | X | X | . | X | X | 4 | 4.00 | 0.500000 | 25.875000 | . | 20.200000 | 21.550000 |
| 6 | X | X | . | X | . | 3 | 3.00 | 1.000000 | 27.266667 | . | 20.266667 | . |
| 7 | X | X | . | . | X | 2 | 2.00 | 0.500000 | 23.400000 | . | . | 18.500000 |
| 8 | X | X | . | . | . | 3 | 3.00 | 1.000000 | 30.900000 | . | . | . |
| EM (Posterior Mode) Estimates | ||||||
|---|---|---|---|---|---|---|
| _TYPE_ | _NAME_ | trt | y1 | y2 | y3 | y4 |
| MEAN | 0.500000 | 26.406000 | 19.156691 | 19.706686 | 22.432206 | |
| COV | trt | 0.235849 | 0.063208 | -2.595558 | -2.056037 | -0.629438 |
| COV | y1 | 0.063208 | 23.338834 | 17.011601 | 17.396964 | 21.818750 |
| COV | y2 | -2.595558 | 17.011601 | 71.635958 | 56.823410 | 32.012830 |
| COV | y3 | -2.056037 | 17.396964 | 56.823410 | 58.773658 | 27.172597 |
| COV | y4 | -0.629438 | 21.818750 | 32.012830 | 27.172597 | 58.692616 |
| Variance Information | |||||||
|---|---|---|---|---|---|---|---|
| Variable | Variance | DF | Relative Increase in Variance |
Fraction Missing Information |
Relative Efficiency |
||
| Between | Within | Total | |||||
| y2 | 0.035413 | 0.764643 | 0.800764 | 92.325 | 0.047239 | 0.045187 | 0.999097 |
| y3 | 0.057276 | 0.633749 | 0.692171 | 87.733 | 0.092184 | 0.084669 | 0.998309 |
| y4 | 0.171957 | 0.626177 | 0.801572 | 70.591 | 0.280106 | 0.220337 | 0.995613 |
| Parameter Estimates | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Variable | Mean | Std Error | 95% Confidence Limits | DF | Minimum | Maximum | Mu0 | t for H0: Mean=Mu0 |
Pr > |t| | |
| y2 | 19.159804 | 0.894854 | 17.38263 | 20.93698 | 92.325 | 18.650950 | 19.577955 | 0 | 21.41 | <.0001 |
| y3 | 19.741783 | 0.831968 | 18.08835 | 21.39521 | 87.733 | 19.279948 | 20.240129 | 0 | 23.73 | <.0001 |
| y4 | 22.375402 | 0.895306 | 20.59003 | 24.16077 | 70.591 | 21.283250 | 23.401187 | 0 | 24.99 | <.0001 |