# MarginalProba: Bayesian test for anteriority / posteriority between two... In ArchaeoPhases: Post-Processing of the Markov Chain Simulated by 'ChronoModel', 'Oxcal' or 'BCal'

 MarginalProba R Documentation

## Bayesian test for anteriority / posteriority between two parameters

### Description

This function estimates the posterior probability that event 'a' is older than event 'b' using the output of the MCMC algorithm. This provides a Bayesian test for checking the following assumption: "Event a is older than event b".

### Usage

```MarginalProba(a_chain, b_chain)
```

### Arguments

 `a_chain` : Numeric vector containing the output of the MCMC algorithm for the first parameter. `b_chain` : Numeric vector containing the output of the MCMC algorithm for the second parameter.

### Details

For a given output of MCMC algorithm, this function estimates the posterior probability of the event 'a' < 'b' by the relative frequency of the event "the value of event 'a' is less than the value of event 'b'" in the simulated Markov chain.

### Value

An unnamed vector with the posterior probability of the assumption: "event a is older than event b"

### Author(s)

Anne Philippe, Anne.Philippe@univ-nantes.fr and

Marie-Anne Vibet, Marie-Anne.Vibet@univ-nantes.fr

### Examples

```
data(Events); attach(Events)
# Probability that Event.1 is older than Event.12
MarginalProba(Event.1, Event.12)
# Probability that Event.1 is older than Event.2
MarginalProba(Event.1, Event.2)
# Probability that the beginning of the phase 1 is older than the end of the phase 1
# Should always be 1 for every phase
data(Phases); attach(Phases)
MarginalProba(Phase.1.alpha, Phase.1.beta)

```

ArchaeoPhases documentation built on March 18, 2022, 5:44 p.m.