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Inverse logit function

Source: R/inv_logit.R
inv_logit.Rd

Inverse logit function

Usage

inv_logit(x)

Arguments

x

Numeric value (usually a logarithm of odds).

Value

Numeric value on the interval \([0,1]\), result of log(pi/(1-pi)).

Numeric value, result of exp(x)/(1+exp(x)).

Details

The inverse logit function is also known as logistic function.

See also

logit()

Examples

# probabilities 
prob_ICE_base <- 0.3
prob_ICE_risk <- 0.6
# model coefficients
(beta1 <- logit(prob_ICE_base))
(beta2 <- logit(prob_ICE_risk) - logit(prob_ICE_base))
# linear predictor 
logit(prob_ICE_base); (lin_pred1 <- beta1 + beta2*0)
logit(prob_ICE_risk); (lin_pred2 <- beta1 + beta2*1)
# inverse logit of linear predictor 
(inv_logit(lin_pred1)) # prob for X1 = 0
(inv_logit(lin_pred2)) # prob for X1 = 1