aic {BAT} | R Documentation |

## Akaike Information Criterion.

### Description

Calculates the Akaike Information Criterion (AIC) of any model based on observed and estimated values.

### Usage

```
aic(obs, est = NULL, param = 0, correct = FALSE)
```

### Arguments

`obs` |
Either a model or a vector with observed values. |

`est` |
A vector with estimated values. Only used if obs is not a model. |

`param` |
Number of parameters in the model. If obs is a model param will be ignored and the number of parameters will be calculated from the model. |

`correct` |
Boolean indicating whether the corrected version of AIC (AICc) should be calculated, mostly for models with few observations. |

### Details

Useful for models or functions that do not provide logLik values.

### Value

The AIC or AICc value.

### Examples

```
obs = c(1,4,5,6)
est = c(0,1,4,7)
#example using values
aic(obs, est)
aic(obs, est, param = 1)
aic(obs, est, param = 1, correct = TRUE)
#example using model
mod = lm(obs ~ est)
aic(mod)
extractAIC(mod)[2]
aic(mod, correct = TRUE)
```

[Package

*BAT*version 2.9.6 Index]