136.9 137.4 136.8 128.8 2 145.5 128.5 121.4 140.7 132.6 计算治疗前后的改变量:gend=x1-x2 二、计算两组的平均改变量: tab group,su(d) group Mean Std. Dev req 1|6.5133347.58415673 15 7.44653966211 15 Total6.9800006.72843602 第2组比第1组多下降0.933318mmHg(即:两组疗效的差异为 0.9333318) 校正治疗前的影响,则用协方差模型 anova d group xl, class(group) Nu of obs Root mse = 525257 Adj R-squared= 0. 4801 Source Partial ss df MS F Prob>F Model|7.9387872823.96939864 14.390.0001 group|5.7457868115.7457868120.830.0001 x1|1.4054753111.40547531 5.090.0323 Residua17.4491645727.275894984 Tota115.387951829.530619029 说明:疗效与基线情况有关,并且两组干预的疗效有差异。 regress ource df MS Number of obs F(2,27)=14.39 Model|7.9387872823.96989364 Prob>f25 2 144.8 136.9 26 2 137.4 129.9 27 2 136.8 128.8 28 2 145.5 139 29 2 128.5 121.4 30 2 140.7 132.6 一、计算治疗前后的改变量：gen d=x1-x2 二、计算两组的平均改变量：tab group, su(d) | Summary of d group | Mean Std. Dev. Freq. ------------+------------------------------------ 1 | 6.5133347 .58415673 15 2 | 7.4466665 .53966211 15 ------------+------------------------------------ Total | 6.9800006 .72843602 30 第 2 组比第 1 组多下降 0.9333318mmHg(即：两组疗效的差异为 0.9333318) 校正治疗前的影响，则用协方差模型 anova d group x1,class(group) Number of obs = 30 R-squared = 0.5159 Root MSE = .525257 Adj R-squared = 0.4801 Source | Partial SS df MS F Prob > F -----------+---------------------------------------------------- Model | 7.93878728 2 3.96939364 14.39 0.0001 | group | 5.74578681 1 5.74578681 20.83 0.0001 x1 | 1.40547531 1 1.40547531 5.09 0.0323 | Residual | 7.44916457 27 .275894984 -----------+---------------------------------------------------- Total | 15.3879518 29 .530619029 说明：疗效与基线情况有关，并且两组干预的疗效有差异。 . regress Source | SS df MS Number of obs = 30 -------------+------------------------------ F( 2, 27) = 14.39 Model | 7.93878728 2 3.96939364 Prob > F = 0.0001