Just for fun, an alternate method.
Names Default To Here( 1 );
dt = open("$sample_data/big class.jmp");
idx = Random Shuffle( dt << Get Rows Where( Column( "sex" )[]== "F" ) );
//get the matching rows but mix up the order;
show(idx); //for demonstration
//use only 5 of them
dtsub = << Subset( rows(idx[1::5]), Output Table( "Best Modules" ) );