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Questions tagged [logistic-regression]

For questions about logistic regressions, a regression model where the dependent variable is categorical.

In statistics, logistic regression is a regression model where the dependent variable is categorical.

We have $$Pr(Y=1|x, \theta) = \frac1{1+\exp(-\theta^Tx)}$$

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Logistic regression (reciprocal of logistic regression coefficient interpretation)

Suppose if a dependent variable is having a disease (1) and not having a disease (0). similarly , independent variable is smoking and not smoking. here , not smoking as reference group. Again, if logistic coefficient of smoking is - 0.3. odd ratio =…
Prasanna
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Logistic regression, when is a "True Positive"?

I have the following table, (LR = Logistic Regression; BA = Biological activity): LR BA 0.539 0 0.526 0 0.527 0 0.597 0 0.508 0 0.536 0 0.507 0 0.546 0 0.552 0 0.456 0 0.529 0 0.527 0 0.454 0 0.546 0 0.528 0 0.531 …
Another.Chemist
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Why is the sigmoid of a linear model equal to the probability of the target being $1$?

From this resource, the writer starts with a linear model: $$ y = \beta_0 + \beta_1 x_1 + \beta_2 x_2 + ... + \beta_m x_m $$ and then makes the RHS sigmoidal. This must then make the LHS sigmoidal to preserve the equality. $$\implies S(y) =…
sangstar
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Can the product of logistic ($x_1$) and logistic ($x_2$) be approximated by logistic ($x_1+x_2$)?

Consider two logistic functions that are multiplied $$ f(x_1,x_2) = \frac{e^{x_1}}{1+e^{x_1}} \times\frac{e^{x_2}}{1+e^{x_2}}=\frac{e^{x_1+x_2}}{1+e^{x_1+x_2}+e^{x_1}+e^{x_2}} $$ To what extent (or under which non-trivial conditions) can this be…
Jorge Guzman
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Logistic regression with arbitrary labels

I am doing logistic regression on some team stats for March Madness, where my response is 1 if "team A wins" and 0 if "team A loses". The problem with that is that the label "team A" is arbitrary. Indeed, my data are naturally labelled as winning…
Him
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