We're gonna call this, um, the game show host problem. All right? Ben, suppose you're on a...

[Ben speaks to his teacher Micky for the first time in class] Micky Rosa: We're gonna call this, um, the game show host problem. All right? Ben, suppose you're on a game show. And you are given a chance to choose from three different doors, all right? Now, behind one of the doors is a new car. Behind the other two, goats. Which door would you choose, Ben? Ben Campbell: Door number one? Micky Rosa: Door number one. Ben chooses door number one. All right, now, the game show host, who, by the way, knows what's behind all the other doors, decides to open another door. Let's say he chooses door number three. Behind which sits a goat, now... Ben, game show host comes to you. He says, 'Ben, do you want to stay with door number one or go with door number two?' Now, is it in your interest to switch your choice? Ben Campbell: Yeah. Micky Rosa: Well, wait. Remember the host knows where the car is, so how do you know he's not playing a trick on you? Trying to use reverse psychology to get you to pick a goat? Ben Campbell: Well, I wouldn't really care. I mean, my answer's based on statistics. Based on variable change. Micky Rosa: Variable change? But he just asked you a simple question. Ben Campbell: Yeah, which changed everything. Micky Rosa: Enlighten us. Ben Campbell: Well, when I was originally asked to choose a door, I had a 33.3% chance of choosing right. But after he opens one of the doors and then re-offers me the choice, it's now 66.7% if I choose to switch. So, yeah, I'll take door number two, and thank you for that extra 33.3%. Micky Rosa: [Micky smiles] Exactly! People, remember, if you don't know which door to open, always account for variable change. Now, see, most people wouldn't take the switch out of paranoia, fear, emotions. But Mr. Campbell, he kept his emotions aside and let simple math get his ass into a brand new car! Which is better than that goat you've been driving around campus.

All right, now, let's give Ben a chance for some extra credit, shall we? We're gonna call this the game show host problem, all right? Ben, suppose you're on a game show. And you are given a chance to choose from three different doors, all right? Now, behind one of the doors is a new car. Behind the other two, goats. Which door would you choose, Ben? Door number one? Door number one. Ben chooses door number one. All right, now, the game show host, who, by the way, knows what's behind all the other doors, decides to open another door. Let's say he chooses door number three. Behind which sits a goat. Now... Ben, game show host comes up to you. He says, "Ben, do you want to stay with door number one "or go with door number two?" Now, is it in your interest to switch your choice? - Yeah. - Well, wait. Remember, the host knows where the car is so how do you know he's not playing a trick on you? Trying to use reverse psychology to get you to pick a goat? Well, I wouldn't really care. I mean, my answer's based on statistics. Based on variable change. Variable change? But he just asked you a simple question. Yeah, which changed everything. Enlighten us. Well, when I was originally asked to choose a door, I had a 33.3% chance of choosing right. But after he opens one of the doors and then re-offers me the choice, it's now 66.7% if I choose to switch. So, yeah, I'll take door number two, and thank you for that extra 33.3%. Exactly. People, remember, if you don't know which door to open, always account for variable change. Now, see, most people wouldn't take the switch out of paranoia, fear, emotions. But Mr. Campbell, he kept emotions aside and let simple math get his ass into a brand-new car! Which is better than that goat you've been driving around campus. All right, everybody. That's the end of the day. Thank you very much. Your graded papers are down here at the end. You can pick them up on your way out. I am invincible. Guys, Jill Taylor, 10 o'clock. Man. That's brutal. You know, you should just ask her out, man. It's not like she's a rocket scientist or anything. Oh, wait, she is. Well, why don't you ask her? Because I'm already dating someone. Yeah, your right hand doesn't count, Miles. It does the way I use it. It does the way I use it. Hey, you know what? Maybe I don't even want to go out with her. Yeah, that's funny. You know, you say you want a life experience, right? Well, I'd say getting down with that would definitely qualify. Cam! Boy genius. You have to follow me now. - Excuse me? - You have to follow me now. Come on. - Where are we going? - You'll see. Our honored guest. - How you doing, Ben? - I'm okay. - You ever been in this room before? - Yeah. Organic Chemistry in my freshman year. - How'd you do? - Well, I got an A.