Table 3: Means and Standard Deviations Before/After Tax Increase Smoking/Nonsmoking Entire sample After Before Diff. Smokers Nonsmokers Diff. # of obs. 297,031 144,251 152,780 57,602 239,429 Smoking 0.19 0.16 0.23 -0.07 (proportion) [0.40] [0.36] [0.42] (-50.64) Birth weight 3416.81 3416.73 3416.88 -0.15 3244.31 3458.30 -214.00 (grams) [556.07] [556.09] [556.07] (-0.07) [561.28] [546.75] (-82.57) Age 28.51 28.70 28.33 .37 27.19 28.82 -1.63 (years) [5.70] [5.75] [5.65] (17.58) [5.67] [5.66] (-62.07) Education 13.46 13.54 13.38 0.15 12.43 13.71 -1.27 [2.50] [2.49] [2.52] (16.48) [2.16] [2.52] (-112.00) Married 0.74 0.74 0.75 -0.004 0.58 0.78 -.20 [0.43] [0.74] [.44] (-2.64) [.49] [0.41] (-90.41) Black 0.10 0.10 0.10 -0.005 0.07 0.11 -0.03 [0.30] [0.29] [.30] (-4.22) [0.26] [0.31] (-27.90) Hispanic 0.10 0.10 0.10 0.002 0.06 0.11 -0.06 [0.30] [0.30] [0.30] (2.23) [.24] [0.32] (-45.34) Kessner=1 0.84 .84 0.83 0.01 0.78 0.85 -0.08 [0.37] [0.36] [0.37] (7.96) [.42] [0.35] (-41.69) Kessner=2 0.13 0.13 0.14 -0.01 0.18 0.12 0.05 [0.34] [0.34] [0.34] (-5.75) [0.38] [0.33] (30.35) Gestation 39.27 39.25 39.29 -0.04 39.14 39.30 -0.17 (weeks) [2.04] [2.01] [2.07] (-5.88) [2.24] [1.99] (-16.29) Note: The table reports means and standard deviations (in brackets) for the sample used in this study. The columns showing differences in means (by assignment or treatment status) report the t-statistic (in parentheses) for the null hypothesis of equality in means. Figure 14: Distribution functions of infant birth weight of smokers and nonsmokers 36