Table 1.

Analysis of Variance Table for a Standard 2 × 2 Crossover Design (Example Data)

Source of variation	d.f.	Type III sum of squares	Mean square	F	P value
Between subjects
Carryover	1	335	335	0.45	0.518
Residual	11	114878	10443
Within-subjects
Treatment	1	14036	14036	18.70	0.001
Period	1	1632	1632	2.17	0.168
Residual	11	8254	750
Total	25	138488

Due to the limitation of the simplified 2 × 2 crossover design, all effects or interactions cannot be estimated separately. Therefore, depending on the model to be designed, the carryover effect is inherent in other effects or interactions. Here, the carryover effect is confirmed through the sequence. That is, in this crossover design model, the carryover effect is inherent in the sequence effect. Therefore, the result for the sequence is displayed as Carryover. d.f.: degrees of freedom.