Table 5: Quantiles of potential outcomes and quantile treatment effects (grams) Figure 16: Estimated quantile curves the monotonized quantile curves for Y$_{0}$ and Y$_{1}$ , respectively. The marginal distribution functions of Y$_{0}$ and Y$_{1}$ are obtained by inverting the monotonized quantile curves. Table 5 presents estimates of quantiles for potential outcomes and QTE. One noticeable observation is that for SCCG women, low quantiles ( q < 0 . 5) of birth weight from smokers are remarkably higher compared to those for the entire sample or other subgroups, while their nonsmokers’ birth weight quantiles are similar to those in other groups. This leads to the lower quantile smoking effects for this college education group compared to other groups at low quantiles. I also obtain the proportion of potential low birth weight infants to smokers and nonsmokers, F$_{0}$ (2 , 500) and F$_{1}$ (2 , 500), respectively. As shown in Table 6, 6.5% of babies to smokers would have low birth weight, 41 (grams) Q$_{0}$$_{.}$$_{15}$ Q$_{0}$$_{.}$$_{25}$ Q$_{0}$$_{.}$$_{5}$ Q$_{0}$$_{.}$$_{75}$ Q$_{0}$$_{.}$$_{85}$ Entire Sample QTE 195 214 234 259 292 Q ( Y$_{0}$ ) 2760 2927 3220 3515 3675 Q ( Y$_{1}$ ) 2955 3141 3454 3774 3967 White QTE 204 212 212 227 255 Q ( Y$_{0}$ ) 2815 2974 3300 3589 3731 Q ( Y$_{1}$ ) 3019 3186 3512 3816 3986 SCCG QTE 109 165 187 244 194 Q ( Y$_{0}$ ) 2908 3031 3316 3566 3798 Q ( Y$_{1}$ ) 3017 3196 3503 3810 3992 Age 26-35 QTE 233 180 179 262 283 Q ( Y$_{0}$ ) 2781 3008 3331 3557 3720 Q ( Y$_{1}$ ) 3014 3188 3510 3818 4003