In other words, between Year 2 and 3 the average learner differs more in what they know and can do, versus Year 8 and 9 where the average learners would be more similar in their skills and knowledge.
Mewn geiriau eraill, yn y flwyddyn waelodlin mae mwy o wahaniaeth o ran sgôr IRT rhwng cyrhaeddiad cyfartalog Blynyddoedd 2 a 3, na rhwng cyrhaeddiad cyfartalog Blynyddoedd 8 a 9.