Hi StataList,
Could you please help me to interpret the coefficients of the following model.
I need to say something like this:
for any a% increase/decrease in weight, the expected ratio of the DAP will be B.
or
we expect about c% increase/decrease in DAP when weight increases/decreases by d%.
I did the following Box-Cox regression:
the results were:
then I did
the results were:
Regards,
Could you please help me to interpret the coefficients of the following model.
Code:
DAP0.2564817=-2.993313+0.9320813*Weight0.2737106+ 0.2308375*DAFrames0.2737106+0.0999711*FluoroFrames0.2737106
I need to say something like this:
for any a% increase/decrease in weight, the expected ratio of the DAP will be B.
or
we expect about c% increase/decrease in DAP when weight increases/decreases by d%.
I did the following Box-Cox regression:
Code:
boxcox DAP Weight DAFrames FluoroFrames , model(theta) lrtest
Code:
Number of obs = 2,811 LR chi2(4) = 2775.64 Log likelihood = -10360.897 Prob > chi2 = 0.000 ------------------------------------------------------------------------------ DAP | Coef. Std. Err. z P>|z| [95% Conf. Interval] -------------+---------------------------------------------------------------- /lambda | .2737106 .0475931 5.75 0.000 .1804299 .3669914 /theta | .2564817 .0169948 15.09 0.000 .2231725 .2897908 ------------------------------------------------------------------------------ Estimates of scale-variant parameters ------------------------------------------------------------- | Coef. chi2(df) P>chi2(df) df of chi2 -------------+----------------------------------------------- Notrans | _cons | -10.64568 -------------+----------------------------------------------- Trans | Weight | .9946927 1273.050 0.000 1 DAFrames | .2463437 508.567 0.000 1 FluoroFrames | .1066865 876.712 0.000 1 -------------+----------------------------------------------- /sigma | .9905126 ------------------------------------------------------------- --------------------------------------------------------------- Test Restricted H0: log likelihood chi2 Prob > chi2 --------------------------------------------------------------- theta=lambda = -1 -13074.245 5426.70 0.000 theta=lambda = 0 -10475.138 228.48 0.000 theta=lambda = 1 -11315.795 1909.80 0.000 ---------------------------------------------------------------
Code:
gen DAP1=DAP^.2564817 gen Weight1=Weight^.2737106 gen DAFrames1=DAFrames^.2737106 gen FluoroFrames1=FluoroFrames^.2737106 regress DAP1 Weight1 DAFrames1 FluoroFrames1
Code:
Source | SS df MS Number of obs = 2,811 -------------+---------------------------------- F(3, 2807) = 1589.88 Model | 308.273108 3 102.757703 Prob > F = 0.0000 Residual | 181.423564 2,807 .064632549 R-squared = 0.6295 -------------+---------------------------------- Adj R-squared = 0.6291 Total | 489.696672 2,810 .174269278 Root MSE = .25423 ------------------------------------------------------------------------------- DAP1 | Coef. Std. Err. t P>|t| [95% Conf. Interval] --------------+---------------------------------------------------------------- Weight1 | .9320813 .0232091 40.16 0.000 .8865728 .9775899 DAFrames1 | .2308375 .0097467 23.68 0.000 .211726 .2499489 FluoroFrames1 | .0999711 .00311 32.15 0.000 .093873 .1060692 _cons | -2.993313 .0857925 -34.89 0.000 -3.161536 -2.82509 -------------------------------------------------------------------------------
Regards,
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