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StratSel (version 1.4)

fetch.rho.b: Function to transform f(\(\rho\)) back to \(\rho\)

Description

The model has a correlation parameter which is estimated and theoretically bound between -1 and +1. To ensure that the estimated parameters are within the theoretical bounds a transformation is necessary. The chosen transformation is:

$$f(\rho): \rho = \frac{2}{(1-exp(-\theta))}- 1$$

Whereas \(\rho\) is the actual correlation coefficient and \(\theta\) is the parameter we estimate in the model. This parametrization has been worked into the likelihood function and ensures that \(\rho\) will be between \(-1\) and \(+1\).

Usage

fetch.rho.b(b)

Value

The function returns the correct estimate for \(\rho\).

Arguments

b

The vector of estimated coefficients (\(\beta\)) whereas the last element is the transformed correlation coefficient (here: \(\theta\)).

Author

Lucas Leemann lleemann@gmail.com

Details

This function is for internal use but documented as a regular function to enable any user to assess the estimator and its functionality.

See Also

StratSel

Examples

Run this code
test <- c(1,1,-2.35)
fetch.rho.b(test)

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