1. Cohen, B. H. (2000). Explaining psychological statistics (2nd ed.). New York: Wiley.
2. Gravetter, F. J. & Wallnau, L. B. (2000). Statistics for the behavioral sciences (5th ed.). Belmont, CA: Wadsworth.
3. Howell, D. C. (1997). Statistical methods for psychology (4th ed.). Belmont, CA: Wadsworth.
4. Keppel, G. (1991). Design and analysis: A researcher's handbook (3rd ed.). Englewood Cliffs, NJ: Prentice Hall.