Yn ôl geiriadur Merriam-Webster
“any of the nine classes into which a set of normalized standard scores arranged according to rank in educational testing are divided, which include the bottom 4 percent and the top 4 percent of the scores in the first and ninth classes and the middle 20 percent in the fifth, and which have a standard deviation of 2 and a mean of 5
Origin and Etymology: standard (score) + nine”
Claire
Sori os cewch chi ddwy neges am y term hwn. Bownsiodd un neges nôl, felly dyma roi ail gynnig arni.
Oes rhywun wedi dod ar draws term am hwn? Maes addysg sydd dan sylw ond alla i ddim cynnig llawer o gyd-destun arall, rwy'n ofni!