Assumption Testing

Besides normality, homogeneity test of variance, and sphericity, Homogeneity of Regression and Linearity are other two assumptions should be tested to apply ANCOVA.

Homogeneity of regression and linearity are another two assumptions of analysis of covariance (ANCOVA). Therefore, to use two-way repeated measures ANCOVA and test the dependent variable of CSA, the regression slopes were checked with the covariate of motivation 1. The results (Table S3) showed that there was not an interaction among cognitive and somatic anxiety, motivation 1 and group, F_(5,78) = 0.456, p = 0.808; there was not an interaction between CSA and group, F_(5,78) = 0.823, p = 0.537; there was not an interaction between CSA and MO1, F_(1,78) = 2.874, p = 0.094. Additionally, the scatterplot was shown in Figure S1.