油耗与重量关系研究

. use auto_zh, clear
(1978年汽车数据)

用散点图显示油耗与重量关系

. scatter 油耗 重量, mcolor(blue%50)

用线性回归研究油耗与重量关系

. regress 油耗 重量

      Source |       SS           df       MS      Number of obs   =        74
-------------+----------------------------------   F(1, 72)        =    194.71
       Model |  87.2964971         1  87.2964971   Prob > F        =    0.0000
    Residual |  32.2797637        72  .448330051   R-squared       =    0.7300
-------------+----------------------------------   Adj R-squared   =    0.7263
       Total |  119.576261        73  1.63803097   Root MSE        =    .66957

------------------------------------------------------------------------------
        油耗 |      Coef.   Std. Err.      t    P>|t|     [95% Conf. Interval]
-------------+----------------------------------------------------------------
        重量 |    .003102   .0002223    13.95   0.000     .0026589    .0035452
       _cons |   .7707669   .3142571     2.45   0.017     .1443069    1.397227
------------------------------------------------------------------------------

线性回归结果显示重量每增加一百公斤,每百公里油耗增加 0.3102公升。