Homework help!!! Paired t-test

I am working on a problem using a paired t-test and fully understand the procedures..However, I am stuck on the dumbest thing.
I can't seem to figure out how to get E(that crazy looking backwards Z)d2.
I have calculated my paired differences and have come up with /d(line supposed to be on top of d) as 0.34. How do I calculate Ed2? Thanks so much.:confused: