Wert, James E, et al. <br/><br/>
Statistical methods in educational and psychological research 

 -  Appleton Century Crofts, New York  1954 
 - 435 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Education-Statistical study
<br/><br/><label>Dewey Class. No.: </label>PG 370.212  WER-S