Thank you Ron. This worked perfectly after minor massaging. I appreciate it. Here is what I ended up with.
dt = Open(
"C:\Users\trcampbell\Desktop\ECOLI\share ecoli data\for Rachel\092921 MODEL\092921 n=205.jmp",
window bounds( 217, 221, 1622, 1057 )
);
Random_rows = dt << Select Randomly( 0.2 ) << Hide and Exclude();
New Column( "Excluded", Numeric, "Continuous", Format( "Best", 12 ) );
:Excluded << Set Formula( If( Excluded(), 1, 0 ) );
dt << Sort( By( :Excluded ), Replace Table, Order( Descending ), Copy formula( 0 ) );
Close(
dt,
save(
"C:\Users\trcampbell\Desktop\ECOLI\share ecoli data\for Rachel\092921 MODEL\test 10 - 092921.jmp"
)
);