Table 2. Analysis of variance table for the data in Table 1.

Source of variation	Degrees of freedom (d.f.)	Sum of squares	Mean square	Variance ratio (F-value)	Pr (>F)
Between groups	2	23,949	11,975	5.79	0.0063
Within groups	39	80,654	2,068

The last column of Table 4 shows the probability to observe a value >6.75 when the null hypothesis is true (Pr(>F)).