S*****z 发帖数: 109 | 1 请教:
logistic regression,
1) if the coefficient of age is positive/ age square is negative, the age
effect is invert U shape.
2) the coefficient of age is negative/age squared is positive, the age
effect is U shape.
But, 如果age和age squared 都是正的或者都是负的呢,age effect是exponential
increasing/decreasing? 大家在做model时会Keep都正或者都负的情形吗?理论上make
sense吗? | s********0 发帖数: 2625 | 2 这个就是初中时候学的一元二次方程的作图。。。。。
y = ax^2 + bx + c, a>0的时候开口向上,a<0的时候开口向下。。。。。 |
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