The guidelines in this appendix help you determine the proper analysis to perform based on your data. In these tables the term Normal indicates that the procedure is based on a normality assumption. The term at least ordinal indicates that the data have an order.
Make decision by reading from the left to the right (Table C.1).
Table C.1 Decision Table for Descriptive Statistics
|What Is the Data Type?||Statistical Procedures/SAS PROC|
|You want to describe a single variable.||Normal||Descriptive statistics: mean, standard deviation, etc.
|Quantitative||Descriptive statistics, median, histogram, boxplots
|You want to describe two related or paired variables.||Both are normal||Pearson's correlation and graphs
|Both are at least ordinal||Spearman's correlation and graphs
|Both are categorical||Cross-tabulation (Chapters 10 and 18)|
Make decision by reading from the left to the right (Table C.2).
Table C.2 Decision Table for Comparison Tests
|What Is the Data Type?||Procedure to Use/SAS PROC|
|You are comparing a single sample to a norm (gold standard).||Normal||Single-sample t-test
|At least ordinal||Sign test |