The y-values must be numbers - that it how Excel knows how high to place
them
You could use a conversion table (90 and above = A, 80 and above = B, etc
Then use one of the chart labeler addins (I recommend Bovey's)
Rob Bovey's Chart Labeler, http://appspro.com
John Walkenbach's Chart Tools, http://j-walk.com
Tushar's Hover Chart Label utility:
http://tushar-mehta.com/excel/softwa...bel/index.html

best wishes
--
Bernard Liengme
http://people.stfx.ca/bliengme
Microsoft Excel MVP

"carol" wrote in message
...
I am trying to plot my students performance in each of their assignments
by
producing a line graph to show whether they have moved up grades but
cannot
chnage the numbers on the y axis to grade letters is this possible?