1. Analgesic study with three treatments crossed with gender.
Two-way ANOVA Example
Analgesic study with three treatments crossed with gender.

2. Data on pain and factor levels
male C 12.4 female A 7.69 male C 14.0 female A 9.69 male C 11.6 female A 8.89 female A 6.94 female A 2.13 female A 7.26 female A 5.87 male B 12.9 female C 12.2 female A 7.20 male C 13.9 male A 8.18
male B 16.6 female C 9.41 male C 11.2 female B 8.35 male A 7.24 female A 6.81 male B 9.81 female A 6.67 female A 6.98 female A 7.07 female C 2.40 male B 7.84 female B 3.84 male B 9.42 male A 7.00 female A 5.00 male A 8.00

3. ANOVA table Source DF Sum of Squares F Ratio Prob > F
gender *
drug *
drug*gender

4. Range Test on Drug Level Least Sq Mean C A 10.316622 B A B 8.710767
Levels not connected by same letter are significantly different.

5. Interaction plots

6. Residual by Predicted

7. Normal Plot

8. Goodness of Fit for Normality
Goodness-of-Fit Test
Shapiro-Wilk W Test
W Prob<W
Note: Ho = The data is from the Normal distribution. Small p-values reject Ho.