Conventional Weibull Regression Model 1 The NLMIXED Procedure Specifications Data Set WORK.HIV Dependent Variable exit Distribution for Dependent Variable General Optimization Technique Dual Quasi-Newton Integration Method None Conventional Weibull Regression Model 2 The NLMIXED Procedure Specifications Data Set WORK.HIV Dependent Variable exit Distribution for Dependent Variable General Optimization Technique Dual Quasi-Newton Integration Method None Dimensions Observations Used 2314 Observations Not Used 0 Total Observations 2314 Parameters 5 Parameters b1 b2 b3 b4 sigma NegLogLike 1 1 1 1 1 2845.74241 Iteration History Iter Calls NegLogLike Diff MaxGrad Slope 1 12 2633.45769 212.2847 263.0096 -11592 2 18 2413.07554 220.3822 1131.59 -546.682 3 24 2299.98256 113.093 218.1204 -1163.99 4 30 2295.41343 4.569124 140.8273 -31.5074 5 42 2274.77575 20.63768 27.33984 -41.6012 6 50 2274.02403 0.751721 21.85087 -5.87421 7 56 2273.23649 0.787535 13.16682 -1.00231 8 63 2272.81492 0.421569 8.524754 -0.55557 9 70 2272.79452 0.020407 2.244654 -0.05301 10 77 2272.79261 0.001902 0.102173 -0.00431 11 84 2272.79256 0.00005 0.030293 -0.00011 12 91 2272.79256 1.011E-6 0.003278 -2.22E-6 NOTE: GCONV convergence criterion satisfied. Fit Statistics -2 Log Likelihood 4545.6 AIC (smaller is better) 4555.6 AICC (smaller is better) 4555.6 BIC (smaller is better) 4584.3 Conventional Weibull Regression Model 3 The NLMIXED Procedure Parameter Estimates Standard Parameter Estimate Error DF t Value Pr > |t| Alpha Lower b1 0.5531 0.04582 2314 12.07 <.0001 0.05 0.4633 b2 0.7070 0.04273 2314 16.55 <.0001 0.05 0.6232 b3 1.8880 0.08979 2314 21.03 <.0001 0.05 1.7119 b4 2.8627 0.08736 2314 32.77 <.0001 0.05 2.6914 sigma 0.9005 0.02434 2314 36.99 <.0001 0.05 0.8527 Parameter Estimates Parameter Upper Gradient b1 0.6430 0.001034 b2 0.7908 0.002208 b3 2.0641 0.001497 b4 3.0340 0.000634 sigma 0.9482 -0.00328 Covariance Matrix of Parameter Estimates Row Parameter b1 b2 b3 b4 sigma 1 b1 0.002099 5.735E-6 0.000076 0.000055 0.000074 2 b2 5.735E-6 0.001826 0.000047 0.000034 0.000046 3 b3 0.000076 0.000047 0.008062 0.000452 0.000608 4 b4 0.000055 0.000034 0.000452 0.007632 0.000440 5 sigma 0.000074 0.000046 0.000608 0.000440 0.000593 Additional Estimates Standard Label Estimate Error DF t Value Pr > |t| Alpha Lower logsigma -0.1049 0.02703 2314 -3.88 0.0001 0.05 -0.1579 RT2-1 1.1663 0.07296 2314 15.99 <.0001 0.05 1.0232 RT3-1 3.7996 0.3801 2314 10.00 <.0001 0.05 3.0542 Additional Estimates Label Upper logsigma -0.05184 RT2-1 1.3094 RT3-1 4.5450 Conventional Weibull Regression Model 4 The NLMIXED Procedure Additional Estimates Standard Label Estimate Error DF t Value Pr > |t| Alpha Lower RT4-1 10.0704 0.9878 2314 10.20 <.0001 0.05 8.1335 RH2-1 0.8429 0.05876 2314 14.34 <.0001 0.05 0.7277 RH3-1 0.2271 0.02487 2314 9.13 <.0001 0.05 0.1783 RH4-1 0.07692 0.009217 2314 8.35 <.0001 0.05 0.05885 Additional Estimates Label Upper RT4-1 12.0074 RH2-1 0.9582 RH3-1 0.2759 RH4-1 0.09500