ciTest: Generic function for conditional independence test

Description

Generic function for conditional independence test. Specializes to specific types of data.

Usage

ciTest(x, set=NULL, ...)
## S3 method for class 'data.frame':
ciTest(x, set=NULL, ...)
## S3 method for class 'table':
ciTest(x, set=NULL, ...)
## S3 method for class 'list':
ciTest(x, set=NULL, ...)

Arguments

An object for which a test for conditional independence is to be made. See 'details' for valid types of x.

set

A specification of the test to be made. The tests are of the form u and v are independent condionally on S where u and v are variables and S is a set of variables. See 'details' for details about specification of set.

...

Additional arguments to be passed on to other methods.

Value

An object of class 'citest' (which is a list).

Details

x can be 1) a table, 2) a dataframe whose columns are numerics and factors or 3) a list with components cov and n.obs. set can be 1) a vector or 2) a right-hand sided formula in which variables are separated by '+'. In either case, it is tested if the first two variables in the set are conditionally independent given the remaining variables in set. (Notice an abuse of the '+' operator in the right-hand sided formula: The order of the variables does matter.)

Examples

Run this code

## contingency table:
data(reinis)
## dataframe with only numeric variables:
data(carcass)
## dataframe with numeric variables and factors:
data(milkcomp1)

ciTest(cov.wt(carcass, method='ML'), set=~Fat11+Meat11+Fat12)
ciTest(reinis, set=~smo+phy+sys)
ciTest(milkcomp1, set=~tre+fat+pro)

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