Statistician joke

An engineer, a physicist, and a statistician all die and go to heaven.
When they arrive at the pearly gate St. Peter stops them and says before you pass through I have a simple question for each of you.
He turns to the engineer and asks, "What's 2 + 2"?
The engineer pulls out his slide ruler, fumbles it around and says, "3.9999".
St. Peter is fine with this answer and says, "Come on in".
He then turns to the physicist and asks the same question, "What's 2 + 2?"
The physicist turns to a chalk board that appears out of no where and writes out this elaborate proof, 2 + 2 = 4
St. Peter is very pleased and says, "Come on in".
He then turns to the Statistican and asks again, "What's 2 + 2"?
The Statistician pauses for a bit, scratches his head and then says, "What do you want it to be?"