In the chapter about はず、

It says when you have a noun you add the particle の before はずです　/　はずだ。 When you are being positive or affirming something.

But what about when you negate it? Would you still add の？

The example given was,
ボビーさん　は　がくせい　ですか？

and the answer was
はい、ボビーさん　は　がくせい　の　はず　だ。

Now, what if you wanted to negate it. What if you wanted to say, No, I expect he is not or was not a student?
Would you say がくせい　じゃない　の　はず　だ　　？？？？