In Reading (Welsh and English) there is a difference in favour of females, whilst in Numeracy there is a difference in favour of males, as is the trend in such assessments in many countries.
O ran Darllen (Cymraeg a Saesneg) mae'r gwahaniaeth o blaid benywod, ac o ran Rhifedd mae'r gwahaniaeth o blaid gwrywod, ac felly y mae'r duedd mewn asesiadau o'r fath mewn llawer o wledydd.