Observed data (N = 111)
  Coef.1 Std. Err. P>t [95% Conf. Interval]
Physical Domain        
HIV + (vs. HIV - ) -7.631 3.505 0.032 -14.592 – -0.669
Psychological Domain        
HIV + (vs. HIV - ) -12.270 2.794 0.000 -17.257 – -6.156
Social Relations Domain        
HIV + (vs. HIV - ) -17.997 3.144 0.000 -24.243 – -11.752
Environmental Domain        
HIV + (vs. HIV - ) -9.700 3.046 0.000 -15.747 – -3.646
1 The coefficients were all adjusted further for age, gender, marital status, education, years of heroin use, study sites, and two biomarkers. Residuals met the normality assumption
Table 2: Average Group Differences in Four Domains of Quality of Life between HIV-positive and HIV-negative Methadone Patients Using Multiple Multivariate Linear Regression.