ThreePLM {exametrika} | R Documentation |
Three-Parameter Logistic Model
Description
The three-parameter logistic model is a model where the lower asymptote parameter c is added to the 2PLM
Usage
ThreePLM(a, b, c, theta)
Arguments
a |
slope parameter |
b |
location parameter |
c |
lower asymptote parameter |
theta |
ability parameter |
Value
Returns a numeric vector of probabilities between c and 1, representing
the probability of a correct response given the ability level theta. The probability
is calculated using the formula: P(\theta) = c + \frac{1-c}{1 + e^{-a(\theta-b)}}
[Package exametrika version 1.1.0 Index]