The girl, Risa Koizumi, is  tall—much taller than the average Japanese girl. The boy, Atsushi Ōtani, is —way below the height of the average Japanese boy.
The girl, Risa Koizumi, is  exceptionally tall—much taller than the average Japanese girl. The boy, Atsushi Ōtani, is —significantly shorter than the height of the average Japanese boy.