The logit and inverse logit functions

Calculates the logit or the inverse logit of a value

logit(prob, base = exp(1))

invlogit(alpha, base = exp(1))

Arguments

prob	vector of probabilities
base	base of the logarithmic function to use
alpha	vector of values to find the inverse logit of

Value

A numeric vector

Examples

logit(0.5)
#> [1] 0

logit(seq(0.01, 0.99, 0.01))
#>  [1] -4.59511985 -3.89182030 -3.47609869 -3.17805383 -2.94443898 -2.75153531
#>  [7] -2.58668934 -2.44234704 -2.31363493 -2.19722458 -2.09074110 -1.99243016
#> [13] -1.90095876 -1.81528997 -1.73460106 -1.65822808 -1.58562726 -1.51634749
#> [19] -1.45001018 -1.38629436 -1.32492541 -1.26566637 -1.20831121 -1.15267951
#> [25] -1.09861229 -1.04596856 -0.99462258 -0.94446161 -0.89538405 -0.84729786
#> [31] -0.80011930 -0.75377180 -0.70818506 -0.66329422 -0.61903921 -0.57536414
#> [37] -0.53221681 -0.48954823 -0.44731222 -0.40546511 -0.36396538 -0.32277339
#> [43] -0.28185115 -0.24116206 -0.20067070 -0.16034265 -0.12014431 -0.08004271
#> [49] -0.04000533  0.00000000  0.04000533  0.08004271  0.12014431  0.16034265
#> [55]  0.20067070  0.24116206  0.28185115  0.32277339  0.36396538  0.40546511
#> [61]  0.44731222  0.48954823  0.53221681  0.57536414  0.61903921  0.66329422
#> [67]  0.70818506  0.75377180  0.80011930  0.84729786  0.89538405  0.94446161
#> [73]  0.99462258  1.04596856  1.09861229  1.15267951  1.20831121  1.26566637
#> [79]  1.32492541  1.38629436  1.45001018  1.51634749  1.58562726  1.65822808
#> [85]  1.73460106  1.81528997  1.90095876  1.99243016  2.09074110  2.19722458
#> [91]  2.31363493  2.44234704  2.58668934  2.75153531  2.94443898  3.17805383
#> [97]  3.47609869  3.89182030  4.59511985
invlogit(-10:10)
#>  [1] 4.539787e-05 1.233946e-04 3.353501e-04 9.110512e-04 2.472623e-03
#>  [6] 6.692851e-03 1.798621e-02 4.742587e-02 1.192029e-01 2.689414e-01
#> [11] 5.000000e-01 7.310586e-01 8.807971e-01 9.525741e-01 9.820138e-01
#> [16] 9.933071e-01 9.975274e-01 9.990889e-01 9.996646e-01 9.998766e-01
#> [21] 9.999546e-01