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arXiv 1402.0845math.STstat.TH
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逻辑斯谛回归系数的符号

The sign of the logistic regression coefficient

Art B. Owen, Paul A. Roediger

摘要:

设Y是一个二元随机变量,X是一个标量。设$\hatβ$为Y对X的逻辑斯谛回归中斜率的最大似然估计值,截距。此外,令$\bar x_0$和$\bar x_1$分别为y=0和y=1情况下的样本x值的平均值。然后在排除可分离预测的条件下,我们证明了sign($\hatβ$)= sign($\bar x_1-\bar x_0$)。更一般地,如果$x_i$是向量值,那么我们证明$\hatβ=0$当且仅当$\bar x_1=\bar x_0$。这适用于逻辑斯谛回归,也适用于更一般的二元回归,其逆连接函数满足对数-对数条件。最后,当设计矩阵满秩时,在满足对数回归条件和分离条件的二元回归中,当$\bar x_1\ne \bar x_0$时,则$\hatβ$和$\bar x_1-\bar x_0$之间的夹角小于90 °。

英文摘要:

Let Y be a binary random variable and X a scalar. Let $\hatβ$ be the maximum likelihood estimate of the slope in a logistic regression of Y on X with intercept. Further let $\bar x_0$ and $\bar x_1$ be the average of sample x values for cases with y=0 and y=1, respectively. Then under a condition that rules out separable predictors, we show that sign($\hatβ$) = sign($\bar x_1-\bar x_0$). More generally, if $x_i$ are vector valued then we show that $\hatβ=0$ if and only if $\bar x_1=\bar x_0$. This holds for logistic regression and also for more general binary regressions with inverse link functions satisfying a log-concavity condition. Finally, when $\bar x_1\ne \bar x_0$ then the angle between $\hatβ$ and $\bar x_1-\bar x_0$ is less than ninety degrees in binary regressions satisfying the log-concavity condition and the separation condition, when the design matrix has full rank.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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