Comparison of Gibbs Sampler to Normal Approximation

The next thing I want to do, is I just want to show you, what's happening, suppose I went back and looked at my estimator and compared it to some kind of normal approximation. Just to see whether it really is important to go through the Gibbs sampler. Here, what I've done, is I've just pulled out the old price sensitivity parameter for Minute Maid and I'm looking at it from the hyper-distribution, so I'm looking at this . So when I got k=5 or when I've got a weaker prior, the point is that the Gibbs estimate, the dashed line and the normal approximation are in agreement. When I start decreasing my prior, what's happening here is that your starting to see some differences here. You know, there's more kurtosis, you know its spread out more and then finally when I come down to k=.1, what's happening here is that if I'm using the normal approximation, I'm going to be quite poorly compared to a Gibbs estimate.

Click here to see the marginal posterior density for hyper-distribution household value effect on premium out-price sensitivity.

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