It was expected that some respondents would be unable to answer all questions and was acknowledged at both the start of the interview and at the start of the written questions.
Roedd disgwyl na fyddai rhai ymatebwyr yn gallu ateb pob cwestiwn a chydnabuwyd hyn ar ddechrau'r cyfweliad ac ar ddechrau'r cwestiynau ysgrifenedig.