add1-drop1 function

Add or drop colour classes to RCOX models

Make a test for adding/dropping all colour classes in scope for an RCOX model.

## S3 method for class 'rcox'
add1(object, scope, details = 0, trace = 0, ...)

## S3 method for class 'rcox'
drop1(object, scope, details = 0, trace = 0, stat = "wald", ...)

Arguments

• object: An RCOX model, an object of class 'rcox'
• scope: A set of edge colour classes to be considered for addition or deletion, see 'details'.
• details: Control the amount of output created.
• trace: For debugging purposes
• ...: Additional arguments, currently unused.
• stat: Either "wald" for a Wald statistic or "dev" for a deviance statistic.

Returns

A list with entries * tab: A dataframe with the test results * cc: A list of colour classes

Note

• Note that the keyword 'stat' is not available for add1 because this function expands the current model and hence the Wald statistic is not available.

• Based on fitting a new model for each new ecc, and may hence be slow.

Examples

data(math)
gc.sat <- ~me:ve:al:st:an
gc.1   <- ~me+ve+al+st+an

m.sat <- rcox(gm=gc.sat, data=math)
m.1   <- rcox(gm=gc.1,   data=math)

t.sat <- drop1(m.sat)
t.sat$tab
t.sat$cc

t.1   <- add1(m.1)
t.1$tab
t.1$cc

See Also

comparecc, stepadd1, stepdrop1.

Author(s)

Søren Højsgaard, sorenh@math.aau.dk