As mentioned above, outliers are holdings on which the change between the base value and the observed value may have a disproportionate effect on the raised estimate.
Fel y soniwyd uchod, eithriadau yw daliadau lle gallai’r newid rhwng y gwerth sylfaenol a’r gwerth a arsylwyd gael effaith anghymesur ar yr amcangyfrif a godir.