(We’re coming up to the first exam of a summer class, for which I’m a TA. We’ve been discussing the importance of study design and accidental influence.)

Professor: “Often, these kinds of things can be hard to predict. Let’s look at a real-life example: when you take exams, there’s always an empty seat between each student. But here in this classroom, you’re all packed in. So, we split you into two rooms. We do this by randomly assigning each student to room A or B. There’s no room actually called, “Room A,” you see, it’s just what we call the two rooms. As you might recognize, both those letters are grades you can get on a test, and we were worried that this might influence the outcomes of the exam. What do you think we found?”

Student #1: “Well… if you’re primed to think you’re going to do well, maybe you’re more relaxed, more confident. So, better exams in room A?”

Professor: “Good! Any other ideas?”

Student #2: “If I’m coming into an exam thinking I’m already in the worse-off group, I’m going to read all the questions carefully, double-check my work, and so on. But if I think, ‘Look at me; I already got an A,’ then maybe I’ll be sloppy.”

Professor: “Also good! Both make sense, both are intuitive. So, [Other Professor] and I got together to study this. We looked up all the grades by room assignment to see what the difference was. We isolated students to switch rooms between midterms and finals to see if they improved or worsened. We even looked into how long they knew their room assignment to see if there was a dose effect. And what do you think we found?”

(There’s pandemonium for a while, while the students argue. Finally, we put it to a vote: 42% think A did better, 14% think B, and the rest don’t think there was a difference.)

Professor: “Despite your votes, the room B students had a higher average! Now… how many of you are checking your emails right now to see who’s in what room tomorrow?”

(Most students sheepishly raise their hands. The rest are too caught up in their laptops.)

Professor: “[Student #3], which are you in tomorrow?”

Student #3: “Uh… 1102? Is that A or…”

Professor: “See, we forgot that the students are just sent the room numbers, and not our little A/B system. So, here’s my last two pieces of information: statistically, flukes do happen occasionally, and we’ve gotten rid of our A/B system entirely!”

(On exam day, I saw that the A/B column I was used to now sorts students into group “A” and group “Other A.”)

(I’m a TA and PhD student. The undergrads are taking summer classes, and most them are new and confused. I’m hurrying to class, and eating a burrito at the same time. Just as I stuff the last of the burrito into my mouth, a lost-looking student stops me.)

Student: “Excuse me, Professor… uh…”

(I look down and notice that my ID card has flipped around. I try to tell him I’m not a professor, but with my mouth full…)

Me: “Mnahprofshr.”

Student: “Oh! I’m looking for Professor Smith. Sorry to bother you, Professor Naprofsher!”

(I tried to correct him, but he escaped while I was laughing and choking on burrito.)

(I am in summer government class. One student pays little attention and randomly chimes in with off topic or invalid points.)

Teacher: “…and the last time there was draft was at the close of the Vietnam war, in 1973.”

Student: “Mm-hmm… That was in World War TWO!”

(I recently started working for the local summer school. After a student got in trouble for leaving the property when she was supposed to be in class, her mother called the school.)

Irate Mother: *after the principal told her why it was a problem* “Well, no one told her she wasn’t allowed to smoke during school!”

(I’m working as a teacher’s assistant in a ‘get ready for second grade’ class. All the kids are seven or eight. Each day we do a math lesson and a writing lesson. Today we are trying to teach the kids about abbreviations.)

Teacher: “Okay, kids who can tell me what ‘Mr.’ stands for?”

Student #1: “Mister.”

Teacher: “Good. How about ‘Ave?'”

Student #2: “Avenue.”

Teacher: “Boy you kids are smart. Okay this is a hard one. Does anyone remember ‘lbs?'”

(The kids look around confused and flip through their work books for the answer. One little boy raises his hand.)

Student #3: “Lullabies?”