Beta priors determination based on different prior information
Beta priors determination based on different prior information
The prior function to calculate the Beta prior parameters
prior(type, mu, v, N, W, init)
Arguments
type: type of prior information: "MeanVar" uses mean and variance, "Optimist" uses (ORR) mean, "ORRN" uses ORR and smaple size, "ORRW" uses ORR and CI width.
mu: prior(ORR) mean.
v: prior variance
N: prior sample size.
W: prior confidence interval width.
init: initial value to solve the nonlinear equations for "ORRW" type.
Returns
parameters: the vector of Beta parameters: a and b
Examples
prior(type ="MeanVar", mu=0.2, v=0.025)prior(type ="Optimist", mu =0.2)prior(type ="ORRN", mu =0.2, N =10)prior(type ="ORRW", mu =0.2, W =0.5)
References
Thall, P. F., Simon, R. (1994). Practical Bayesian guidelines for phase IIB clinical trials. Biometrics 50 : 337-349.
Mayo, M. S., & Gajewski, B. J. (2004). Bayesian sample size calculations in phase II clinical trials using informative conjugate priors. Controlled clinical trials 25 (2): 157-167.
Tan, S. B., & Machin, D. (2002). Bayesian two-stage designs for phase II clinical trials. Statistics in medicine 21 (14): 1991-2012. New York: Wiley.