Difference between revisions of "Logit"
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:[[image:logitGraph.png]] | :[[image:logitGraph.png]] | ||
− | The inverse of the [[Logit]] function is [[Sigmoid]](x) (before [[Analytica 4.5]], the function [[InvLogit]] was used, defined in the | + | The inverse of the [[Logit]] function is [[Sigmoid]](x) (before [[Analytica 4.5]], the function [[InvLogit]] was used, defined in the [[media:Generalized Regression.ana|Generalized Regression library]]). The logit function is sometimes called the log-odds function. |
== Library == | == Library == | ||
− | |||
Advanced Math Functions | Advanced Math Functions | ||
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==History== | ==History== | ||
− | [[Logit]] was introduced as a built-in function in [[Analytica 4.5]]. Before that, it was supplied as a function in the | + | [[Logit]] was introduced as a built-in function in [[Analytica 4.5]]. Before that, it was supplied as a function in the [[media:Generalized Regression.ana|Generalized Regression library]]. |
== See Also == | == See Also == | ||
* [[Sigmoid]](x) | * [[Sigmoid]](x) | ||
* [[LogisticRegression]] | * [[LogisticRegression]] |
Revision as of 22:02, 24 February 2016
Logit(p)
The Logit function is equal to
- [math]\displaystyle{ Logit(p) = \ln\left( p\over{1-p} \right) }[/math]
where [math]\displaystyle{ 0\lt p\lt 1 }[/math].
The inverse of the Logit function is Sigmoid(x) (before Analytica 4.5, the function InvLogit was used, defined in the Generalized Regression library). The logit function is sometimes called the log-odds function.
Library
Advanced Math Functions
Complex numbers
When p < 0 or p > 1, a warning is issued and if the warning is ignored, the result is NaN. This is the case unless you have enabled complex numbers. If you have set the system variable EnableComplexNumbers to 1, then no warning is issued and Logit(p) returns a complex number.
History
Logit was introduced as a built-in function in Analytica 4.5. Before that, it was supplied as a function in the Generalized Regression library.
See Also
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