Table 3.

Analysis of variance (ANOVA) for a 2 × 2 cross-over study.

Source of Variation	Partial SS	df	MS	F	P value
Treatment effect	449.56	1	449.56	5.43	0.027
Period effect	327.06	1	327.06	3.95	0.057
Treatment * Period	7.38	1	7.38	0.09	0.768
Residuals	2319.94	28	82.85
Total	3018.88	31

SS (Sum of Squares): The total variation attributable to each source.

df (Degrees of Freedom): The number of values that are free to vary for each source.

MS (Mean Square): The average variation, calculated by dividing the sum of squares (SS) by its respective degrees of freedom (df).

F (F-statistic): The test statistic obtained by dividing the MS of a factor by the MS of the residuals; used to determine statistical significance.