RDCHEM.DES rd sales profits rdintens profmarg salessq lsales lrd Obs: 32 1. rd R&D spending, millions $ 2. sales firm sales, millions $ 3. profits profits, millions $ 4. rdintens rd as percent of sales 5. profmarg profits as percent of sales 6. salessq sales^2 7. lsales log(sales) 8. lrd log(rd)