For some results, responses are re-categorised into the following three groups: ‘Very good or Good’, ‘Fair’, ‘Bad or Very bad’.
Yn achos rhai canlyniadau, caiff yr ymatebion eu hailddosbarthu i’r tri grŵp a ganlyn: ‘Da iawn neu Dda’, ‘Gweddol’, ‘Gwael neu Wael iawn’.