The three-parameter logistic model is a model where the lower
asymptote parameter c is added to the 2PLM
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: \(P(\theta) = c + \frac{1-c}{1 + e^{-a(\theta-b)}}\)
