Z Score for multiple classes w/ different grades

D

devavejay

Guest
#1
calculating z scores

Grades class
a 1
a 1
a 3
b 1
b 2
b 3
b 3
c 1
c 3
c 2
d 2
d 2
a 1

How do you calculate the Z score for this?

Do you break it down by class? and calc each class's Z score for each grade?
The intent is to normalize the grades across classes, and I am a bit confused on how to do that.