It should be noted, in this context, that tests of significance for squared semi-partial correlation coefficients are sensitive to deviations from the assumptions of normality and homogeneity (Algina, Keselman, & Penfield, 2007, 2010).
As in the analysis of variance approach, under H0 the distribution of each F ratio is Snedecor’s F distribution with 1 df in the numerator and N − g df in the denominator.
The two approaches, analysis of variance for trend and polynomial multiple regression, yield the same F ratios and the same probability values.