Grade Percentile threshold Probit RSR threshold (Fitted value)
Grade 1 96.407 ~ 6.8 ~ 0.5109 ~
Grade 2 72.575 ~ 5.6 ~ 0.3946 ~
Grade 3 27.425 ~ 4.4 ~ 0.2784 ~
Grade 4 3.593 ~ 3.2 ~ 0.1621 ~
Grade 5 <3.593 <3.2 <0.1621