gRim (version 0.3.4)

citest-generic: Generic function for conditional independence test

Description

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

Usage

ciTest(x, set = NULL, ...)

Value

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

Arguments

x

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.

Author

Søren Højsgaard,

Details

x can be

1. a table (an array). In this case ciTest_table is called.

2. a dataframe whose columns are numerics and factors. In this case ciTest_df is called.

3. a list with components cov and n.obs. In this case ciTest_mvn is called.

set can be

1. a vector,

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.)

See Also

ciTest_table, ciTest_df, ciTest_mvn, chisq.test

Examples

## 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)