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NPP (version 0.6.0)

BerOMNPP_MCMC1: MCMC Sampling for Bernoulli Population of multiple ordered historical data using Normalized Power Prior

Description

Multiple ordered historical data are incorporated together. Conduct posterior sampling for Bernoulli population with normalized power prior. For the power parameter \(\gamma\), a Metropolis-Hastings algorithm with independence proposal is used. For the model parameter \(p\), Gibbs sampling is used.

Usage

BerOMNPP_MCMC1(n0, y0, n, y, prior_gamma, prior_p, gamma_ind_prop,
                   gamma_ini, nsample, burnin, thin, adjust = FALSE)

Value

A list of class "NPP" with three elements:

acceptrate

the acceptance rate in MCMC sampling for \(\gamma\) using Metropolis-Hastings algorithm.

p

posterior of the model parameter \(p\).

delta

posterior of the power parameter \(\delta\). It is equal to the cumulative sum of \(\gamma\).

Arguments

n0

a non-negative integer vector: number of trials in historical data.

y0

a non-negative integer vector: number of successes in historical data.

n

a non-negative integer: number of trials in the current data.

y

a non-negative integer: number of successes in the current data.

prior_gamma

a vector of the hyperparameters in the prior distribution \(Dirichlet(\alpha_1, \alpha_2, ... ,\alpha_K)\) for \(\gamma\).

prior_p

a vector of the hyperparameters in the prior distribution \(Beta(\alpha, \beta)\) for \(p\).

gamma_ind_prop

a vector of the hyperparameters in the proposal distribution \(Dirichlet(\alpha_1, \alpha_2, ... ,\alpha_K)\) for \(\gamma\).

gamma_ini

the initial value of \(\gamma\) in MCMC sampling.

nsample

specifies the number of posterior samples in the output.

burnin

the number of burn-ins. The output will only show MCMC samples after burnin.

thin

the thinning parameter in MCMC sampling.

adjust

Logical, indicating whether or not to adjust the parameters of the proposal distribution.

Author

Qiang Zhang zqzjf0408@163.com

Details

The outputs include posteriors of the model parameter(s) and power parameter, acceptance rate in sampling \(\gamma\). The normalized power prior distribution is given by: $$\frac{\pi_0(\gamma)\pi_0(\theta)\prod_{k=1}^{K}L(\theta|D_{0k})^{(\sum_{i=1}^{k}\gamma_i)}}{\int \pi_0(\theta)\prod_{k=1}^{K}L(\theta|D_{0k})^{(\sum_{i=1}^{k}\gamma_i)}d\theta}.$$ Here, \(\pi_0(\gamma)\) and \(\pi_0(\theta)\) are the initial prior distributions of \(\gamma\) and \(\theta\), respectively. \(L(\theta|D_{0k})\) is the likelihood function of historical data \(D_{0k}\), and \(\sum_{i=1}^{k}\gamma_i\) is the corresponding power parameter.

References

Ibrahim, J.G., Chen, M.-H., Gwon, Y. and Chen, F. (2015). The Power Prior: Theory and Applications. Statistics in Medicine 34:3724-3749.

Duan, Y., Ye, K. and Smith, E.P. (2006). Evaluating Water Quality: Using Power Priors to Incorporate Historical Information. Environmetrics 17:95-106.

See Also

BerMNPP_MCMC1, BerMNPP_MCMC2, BerOMNPP_MCMC2

Examples

Run this code
BerOMNPP_MCMC1(n0 = c(275, 287), y0 = c(92, 125), n = 39, y = 17, prior_gamma=c(1,1,1)/3,
               prior_p=c(1/2,1/2), gamma_ind_prop=rep(1,3)/2, gamma_ini=NULL,
               nsample = 2000, burnin = 500, thin = 2, adjust = FALSE)

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