The professor asked "how many believe in ghosts?"

Almost half the class held up their hands

The professor then asked "how many have seen a ghost?"

More than a quarter to the class held up their hands

The professor then asked "How many have talked to a ghost?"

And three students held up their hands

Finally the professor asked "How many have had sex with a ghost?"

One student, a Muslim in the rear, held up his hand.

The professor walked back to the student, and asked "So you've actually had sex with a ghost?"

The student looked at the professor, a surprised look on his face, and muttered "I though you said goats..."