Emphasizing the logic of statistical principles, this text provides students with guidelines for deciding when to use various procedures. It covers descriptive and inferential statistics, and procedures for assessing practical significance are emphasized over statistical significance. Expanded topics include confidence intervals, visual approaches to understanding data such as box plots and confidence interval graphs, and procedures for detecting outliers. ALso included are multiple comparison procedures and discussions of printouts from three microcomputer statistics packages - JMP, SPSS and SYSTAT.