$-\mathrm{C}{\mathrm{H}}_3$ group is inductively electron-donating and base-strengthening from all position. Moreover, if $-\mathrm{C}{\mathrm{H}}_3$ is attached to benzene ring (or if R has benzylic H), it is electron-donating by hyper-conjugation from the ortho and para positions. Because of ortho effect, o-substituted aniline become less basic than aniline. Thus,

$\mathrm{p}-\mathrm{C}{\mathrm{H}}_3{\mathrm{C}}_6{\mathrm{H}}_4\mathrm{N}{\mathrm{H}}_2$ (hyper-conjugation and induction) > $\mathrm{m}-\mathrm{C}{\mathrm{H}}_3{\mathrm{C}}_6{\mathrm{H}}_4\mathrm{N}{\mathrm{H}}_2$ (induction) > ${\mathrm{C}}_6{\mathrm{H}}_5\mathrm{N}{\mathrm{H}}_2>\mathrm{o}-\mathrm{C}{\mathrm{H}}_3{\mathrm{C}}_6{\mathrm{H}}_4\mathrm{N}{\mathrm{H}}_2$ (ortho effect).