Contenido: 1. Introduction -- 2. Tabular and graphic methods -- 3. Describing frequency distributions -- 4. Distribution curves -- 5. Probability and hypothesis testing -- 6. Inference: continuous variables -- 7. Small sample or t technique -- 8. Correlation: introduction and computation -- 9. Correlation: interpretations and assumptions -- 10. Factors wich affect the correlation coefficient -- 11. Multiple correlation -- 12. Other correlation methods -- 13. Frequency comparison: chi square -- 14. Inferences about variabilities -- 15. Analysis of variance: simple -- 16. Analysis fo variance: complex -- 17. Trends and differences in trends -- 18. Analysis of variance: covariance method -- 19. Distribution-free methods -- 20. Remarks on error reduction -- Exercises -- Appendix