logistic function

Logistic Model

The model function for the logistic model is defined as [REMOVE_ME]$f(d, \theta) = E_0 + E_{\max}/\left\{1 + \exp\left[ \left(ED_{50} - d\right)/\delta \right] \right\}f(d,theta)=E0+Emax/(1 + exp((ED50-d)/delta)). [REMOVE_ME_2]$

Description

The model function for the logistic model is defined as

logistic(dose, e0, eMax, ed50, delta)

Arguments

• dose: Dose variable
• e0: Left-asymptote parameter, corresponding to a basal effect level (not the placebo effect, though).
• eMax: Asymptotic maximum change in effect from the basal level.
• ed50: Dose giving half of the asymptotic maximum effect.
• delta: Parameter controlling determining the steepness of the curve.

Details

The logistic model is intended to capture general monotone, sigmoid dose-response relationships.

Returns

Response value

References

Pinheiro, J. C., Bretz, F. and Branson, M. (2006). Analysis of dose-response studies - modeling approaches, in N. Ting (ed.). Dose Finding in Drug Development, Springer, New York, pp. 146--171

See Also

betaMod, logistic, sigEmax, linlog, linear, quadratic, exponential