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arXiv 1506.03481stat.MEmath.STstat.TH
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关于近似贝叶斯计算估计量的渐近有效性

On the Asymptotic Efficiency of Approximate Bayesian Computation Estimators

Wentao Li, Paul Fearnhead

摘要:

许多统计应用涉及的模型,很难评估的可能性,但它是相对容易的样本。近似贝叶斯计算是在这种情况下实现贝叶斯推断的无似然方法。我们目前的结果估计的渐近方差使用近似贝叶斯计算在大数据限制。我们的关键假设是,数据是由一个固定维的汇总统计,服从中心极限定理。我们证明了近似贝叶斯计算后验均值的渐近正态性。这个结果还表明,在渐近方差方面,我们应该使用与参数向量p维数相同的汇总统计量;并且任何更高维数的汇总统计量都可以通过线性变换以仅能减少后验均值的渐近方差的方式减少到维数p。我们看看如何蒙特卡罗误差的重要性抽样算法的样本从近似贝叶斯计算后影响估计的准确性。我们给出了重要性抽样建议分布的条件,使得估计量的方差与基于汇总统计量的极大似然估计量的方差为同一阶。这表明了一个迭代的重要性抽样算法,我们经验评估的随机波动率模型。

英文摘要:

Many statistical applications involve models for which it is difficult to evaluate the likelihood, but from which it is relatively easy to sample. Approximate Bayesian computation is a likelihood-free method for implementing Bayesian inference in such cases. We present results on the asymptotic variance of estimators obtained using approximate Bayesian computation in a large-data limit. Our key assumption is that the data are summarized by a fixed-dimensional summary statistic that obeys a central limit theorem. We prove asymptotic normality of the mean of the approximate Bayesian computation posterior. This result also shows that, in terms of asymptotic variance, we should use a summary statistic that is the same dimension as the parameter vector, p; and that any summary statistic of higher dimension can be reduced, through a linear transformation, to dimension p in a way that can only reduce the asymptotic variance of the posterior mean. We look at how the Monte Carlo error of an importance sampling algorithm that samples from the approximate Bayesian computation posterior affects the accuracy of estimators. We give conditions on the importance sampling proposal distribution such that the variance of the estimator will be the same order as that of the maximum likelihood estimator based on the summary statistics used. This suggests an iterative importance sampling algorithm, which we evaluate empirically on a stochastic volatility model.

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