Robert A. Schneider 
Basic Statistics for Social Workers [PDF ebook] 

Basic Statistics for Social Workers, now in a revised edition, was developed by Schneider after teaching statistics to undergraduate and graduate social work students for over ten years. The statistical concepts that are necessary for students to know are covered, ranging from simple descriptive statistics such as crosstabs and tabular data up to a limited discussion of multiple regression. The text is written simply for students who may not have a strong quantitative background. The text is simple enough that with the practice problems and perhaps a little consultation a motivated student could self-teach the content.