# EBpostthresh

From SpatialEpi v1.2.3
by Albert Kim

##### Produce the probabilities of exceeding a threshold given a posterior gamma distribution.

This function produces the posterior probabilities of exceeding a threshold given a gamma distributions with parameters (alpha+Y, (alpha+E*mu)/mu) where mu = exp(x beta). This model arises from Y being Poisson with mean theta times E where theta is the relative risk and E are the expected numbers. The prior on theta is gamma with parameters alpha and beta. The parameters alpha and beta may be estimated using empirical Bayes.

- Keywords
- file

##### Usage

`EBpostthresh(Y, E, alpha, beta, Xrow = NULL, rrthresh)`

##### Arguments

- Y
observed disease counts

- E
expected disease counts

- alpha
- beta
- Xrow
- rrthresh

##### Value

Posterior probabilities of exceedence are returned.

##### See Also

##### Examples

```
# NOT RUN {
data(scotland)
Y <- scotland$data$cases
E <- scotland$data$expected
ebresults <- eBayes(Y,E)
# Find probabilities of exceedence of 3
thresh3 <- EBpostthresh(Y, E, alpha=ebresults$alpha, beta=ebresults$beta,
rrthresh=3)
mapvariable(thresh3, scotland$spatial.polygon)
# }
```

*Documentation reproduced from package SpatialEpi, version 1.2.3, License: GPL-2*

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