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老师,请问,utest检测显示最大值不在自变量取值范围内,操作如下:
Specification: f(x)=x^2
Extreme point: 16.97328
Test:
H1: Inverse U shape
vs. H0: Monotone or U shape
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| Lower bound Upper bound
-----------------+-------------------------------
Interval | .1528926 .40909
Slope | .2959529 .2914451
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Extremum outside interval - trivial failure to reject H0
95% Fieller interval for extreme point: [6.8333875; 34.595769]
. sum EI
Variable | Obs Mean Std. Dev. Min Max
-------------+---------------------------------------------------------
EI | 2,909 .231224 .0566638 .1528926 .40909
但是,用marginsplot画图、twoway(qfit FP_hat EI),图像显著在自变量取值范围内存在最大值。请问,utest检测结果为什么会跟图像相反呢?
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