Hello,<br/><br/>Is the following correct?<br/><br/><u>1) A comparison of training costs between senior managers and factory workers</u> can be useful.<br/><br/>Some seem to use<br/><br/><u>2) A comparison of training costs for senior managers and factory workers</u> can be useful.<br/><br/><u>3) A comparison of training costs for senior managers with those for factory workers</u> can be useful.<br/><br/>WHich is correct? Are they all correct?<br/><br/>Which is used most frquently?<br/><br/>Thanks!