Elements of statistics 
Mode, Elmer B. 
 - Third edition. 
 -  Prentice Hall Inc.  1961 
 - 319 pages. 
<br/><br/>
<br/><br/><label>ISBN: </label>9-71080814-1 
<br/><br/><label>Dewey Class. No.: </label>519.5 M72 1961