Determining numeric "rule" used for a categorical variable

[kinnari trivedi]

Hi,

I'm trying to figure out what "rule" has been used for assigning letter grades in my data. I have observations each with a numeric score and an associated letter grade, and I want to determine how the grades have been assigned. Does anyone have advice/hints for me?

[Nick Cox]

tabstat score, s(min max) by(grade)