The GBTS data are weighted to correct for any imperfections in the achieved sample that might lead to bias and to rectify any differences between the sample and the target GB population.
Caiff data'r GBTS eu pwysoli i gywiro unrhyw amherffeithrwydd yn y sampl a gyflawnwyd a allai arwain at duedd ac i unioni unrhyw wahaniaethau rhwng y sampl a phoblogaeth darged Prydain Fawr.