gRim (version 0.3.4)

citest-df: Test for conditional independence in a dataframe

Description

Test for conditional independence in a dataframe.

Usage

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

Value

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

Arguments

x

A dataframe.

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.

Author

Søren Højsgaard,

Details

• 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.)

• If set is NULL then it is tested whether the first two variables are conditionally independent given the remaining variables.

• If set consists only of factors then x[,set] is converted to a contingency table and the test is made in this table using ciTest_table().

• If set consists only of numeric values and integers then x[,set] is converted to a list with components cov and n.obs by calling cov.wt(x[,set], method='ML'). This list is then passed on to ciTest_mvn() which makes the test.

See Also

ciTest, ciTest_table, ciTest_mvn, chisq.test

Examples

data(milkcomp1)
ciTest(milkcomp1, set=~tre + fat + pro)
ciTest_df(milkcomp1, set=~tre + fat + pro)