Evelyn Davis & Steven Davis 
Data Analysis with SPSS Software [PDF ebook] 
Linear Regression and Non-Parametric Test

Building on the tools and techniques found in the popular statistics computer program, SPSS, this series of six books introduces the reader to the concepts of data, their categorical types, how data can be organized and manipulated, and how they can be put to practical use in solving everyday problems in science, business and technology. This fifth of 6 books introduces the important concept of linear regression analysis, and how it is used to create a best fit with data with two variables. It explains the coefficient of determination and the coefficient of alienation, as well as the concept of residuals. It then goes on to explain the Chi-Square Distribution, including the goodness-of-fit test, and understanding the assumptions and degrees of freedom when performing a Chi-Square test. Worked out exercises help to clarify the principles explained in the book.