Correlated covariates in ANCOVA cannot adjust for pre-existing differences between groups.
Suckling
John
J
D000704:Analysis of Variance; D003072:Cognition Disorders / Q000175:diagnosis / Q000209:etiology; D006801:Humans; D012107:Research Design; D012559:Schizophrenia / Q000150:complications; D013223:Statistics as Topic