What statistcal tool do I use in SPSS to correlate grades from a test (expressed as a percent) with a letter grade from another class?

Thanks,
Allie

I am assuming it is the letter grade part of this problem that is confusing you.

I would convert the letter grade to numbers using whatever scale you feel is appropriate (for example, B=3.00, B+ = 3.33, A- = 3.67, A=4.0).

Now you have two tests with numerical scores.

Once you have done that, does the remainder of your problem make more sense?

Thanks for your feedback. I guess I was having trouble resolving grade points as interval data, but since we use it to calculate grade point averages it must be quasi-valid.