invlogit: Logistic and Inverse logistic functions In arm: Data Analysis Using Regression and Multilevel/Hierarchical Models

Description

Inverse-logit function, transforms continuous values to the range (0, 1)

Usage

 ```1 2``` ```logit(x) invlogit(x) ```

Arguments

 `x` A vector of continuous values

Details

The Inverse-logit function defined as: logit^-1(x) = e^x/(1+e^x) transforms continuous values to the range (0, 1), which is necessary, since probabilities must be between 0 and 1 and maps from the linear predictor to the probabilities

Value

A vector of estimated probabilities

Author(s)

Andrew Gelman [email protected], M.Grazia Pittau [email protected]

References

Andrew Gelman and Jennifer Hill. (2006). Data Analysis Using Regression and Multilevel/Hierarchical Models. Cambridge University Press.

Examples

 ```1 2 3 4 5 6 7 8 9``` ``` data(frisk) n <- 100 x1 <- rnorm (n) x2 <- rbinom (n, 1, .5) b0 <- 1 b1 <- 1.5 b2 <- 2 Inv.logit <- invlogit(b0+b1*x1+b2*x2) plot(b0+b1*x1+b2*x2, Inv.logit) ```

Example output

```Loading required package: MASS