question: public IndependenceTest indTestSubset ( List vars ) { if ( vars . isEmpty ( ) ) { throw new IllegalArgumentException ( "Subset may not be empty." ) ; } int [ ] indices = new int [ vars . size ( ) ] ; int j = - 1 ; for ( int i = 0 ; i < variables . size ( ) ; i ++ ) { if ( ! vars . contains ( variables . get ( i ) ) ) { continue ; } indices [ ++ j ] = i ; } DataSet newDataSet = dataSet . subsetColumns ( indices ) ; return new IndTestGSquare ( newDataSet , alpha ) ; }
target:  Creates a new IndTestGSquare for a subset of the variables.