modavg.utility {AICcmodavg} | R Documentation |

## Various Utility Functions

### Description

`reverse.parm`

and `reverse.exclude`

reverse the order of
variables in an interaction term.

`formatCands`

creates new classes for lists containing candidate
models.

`formulaShort`

prints a succinct formula from an `unmarkedFit`

object.

### Usage

```
reverse.parm(parm)
reverse.exclude(exclude)
formatCands(cand.set)
formulaShort(mod, unmarked.type = NULL)
```

### Arguments

`parm` |
a parameter to be model-averaged, enclosed between quotes, as it appears in the output of some models. |

`exclude` |
a list of interaction or polynomial terms appearing in some models, as
they would appear in the call to the model function (i.e., |

`cand.set` |
a list storing each of the models in the candidate model set. |

`mod` |
an object storing the result of an |

`unmarked.type` |
a character string specifying the type of parameter in
an |

### Details

These utility functions are used internally by `aictab`

,
`modavg`

, and other related functions.

`reverse.parm`

and `reverse.exclude`

enable the user to
specify differently interaction terms (e.g., `A:B`

, `B:A`

)
across models for model averaging. These functions have been added to
avoid problems when users are not consistent in the specification of
interaction terms across models.

`formatCands`

creates new classes for the list of candidate
models based on the contents of the list. These new classes are used
for method dispatch.

`formulaShort`

is used by `anovaOD`

.

### Value

`reverse.parm`

returns all possible combinations of an interaction
term to identify models that include the `parm`

of interest and
find the corresponding estimate and standard error in the model object.

`reverse.exclude`

returns a list of all possible combinations of
`exclude`

to identify models that should be excluded when
computing a model-averaged estimate.

`formatCands`

adds a new class to the list of candidate
models based on the classes of the models.

`formulaShort`

creates a character string for the formula related
to a given parameter type from an `unmarkedFit`

object.

### Author(s)

Marc J. Mazerolle

### See Also

`aictab`

, `anovaOD`

, `modavg`

,
`modavgShrink`

, `modavgPred`

### Examples

```
##a main effect
reverse.parm(parm = "Ageyoung") #does not return anything
##an interaction term as it might appear in the output
reverse.parm(parm = "Ageyoung:time") #returns the reverse
##exclude two interaction terms
reverse.exclude(exclude = list("Age*time", "A:B"))
##returns all combinations
reverse.exclude(exclude = list("Age:time", "A*B"))
##returns all combinations
##Mazerolle (2006) frog water loss example
data(dry.frog)
##setup a subset of models of Table 1
Cand.models <- list( )
Cand.models[[1]] <- lm(log_Mass_lost ~ Shade + Substrate +
cent_Initial_mass + Initial_mass2,
data = dry.frog)
Cand.models[[2]] <- lm(log_Mass_lost ~ Shade + Substrate +
cent_Initial_mass + Initial_mass2 +
Shade:Substrate, data = dry.frog)
Cand.models[[3]] <- lm(log_Mass_lost ~ cent_Initial_mass +
Initial_mass2, data = dry.frog)
formatCands(Cand.models)
## Not run:
require(unmarked)
data(bullfrog)
bfrog <- unmarkedFrameOccu(y = bullfrog[, c("V1", "V2", "V3", "V4")],
siteCovs = bullfrog[, 1:2])
fm1 <- occu(~ 1 ~ Reed.presence, data = bfrog)
formulaShort(fm1, unmarked.type = "state")
formulaShort(fm1, unmarked.type = "det")
## End(Not run)
```

*AICcmodavg*version 2.3-3 Index]