Simulation results summarizing the estimates of the “slope” coefficient obtained by AME, LS, LAD, and ZQR, for both the AEPD and non-AEPD error distributions. This summary includes the average estimate minus the true value (Bias), relative efficiency (Eff), estimated coverage probability (Cov) associated with 95% confidence intervals, and averaged confidence interval length (AL). Here t3 denotes Student’s t-distribution with 3 degrees of freedom; denotes a Chi-square distribution with 3 degrees of freedom; SN(4) denotes a skewed normal distribution with a slant parameter of 4; ST(3,0.5) for skewed t-distribution with 3 degrees of freedom and a skewing parameter of 0.5.