For relevel
you need to specify the level label exactly as it appear in the factor:
glm( TargetVar ~ relevel(cut_Var3,"(3,6]"), data = dat)
Call: glm(formula = TargetVar ~ relevel(cut_Var3, "(3,6]"), data = dat)
Coefficients:
(Intercept) relevel(cut_Var3, "(3,6]")(0,3]
0.75 -0.35
relevel(cut_Var3, "(3,6]")(6,9]
-0.50
Degrees of Freedom: 12 Total (i.e. Null); 10 Residual
(1 observation deleted due to missingness)
Null Deviance: 3.231
Residual Deviance: 2.7 AIC: 24.46