Statistics :  a Tool for Social Research  / 
Joseph Healey , Steven G Prus . 
 - Toronto:  Nelson Education ,  2010. 
 - xxiv,586 p.:  ill. 
<br/><br/><label>ISBN: </label>9780176442538 
<br/><br/><label>LC Class. No.: </label>HA29  / .H42 2010