Yesterday was a good day for teaching. There really wasn’t anything special about it except that I let myself be a nerd in front of the class. Ordinarily, I try my hardest not to make a fool of myself in front of the classroom, but this time I decided, “I like statistics – they excite me, and I’m going to SHOW it!” So, in explaining how we sum scores to get an overall mean, I started talking about Harry Potter. That’s right. As fascinating as the ole’ textbook example of how room illumination affects reading speed is, I decided I was done with that. So I told them, let’s pretend I have 100 students’ data (n = 100) on how much they like Harry Potter. I ask each student, on a scale of 1 to 7 (1 = not at all, 7 = abso-freakin-lutely!) “How much do you like the Harry Potter series?” Well, Bob really loves Harry Potter, so he rates himself at a 7. He represents my first variable (X1 = 7) or score. Then Sally didn’t love it, so she puts a two (X2 = 2, which is my second variable or score), and on and on I go for 100 students. But wouldn’t be easier if I could just denote that function with summation notation? Well, I can! And this summation notation can be used to tell me to sum everyone’s scores, divide it by the number of scores, and get the average rating of Harry Potter. Et voila! The mean.
Ordinarily, I stop here because that’s all they have to learn this lesson. But no, why should lessons determine how cool class is? So I let them in on a secret – a teaser if you will. I said, “Now here’s where it gets REALLY fun! Do we want to know if men and women like Harry Potter more? Well, we can figure that out! I just get the mean of men’s attitudes toward Harry Potter and women’s attitudes and I compare them using some really cool statistics. Soon, you’ll learn how to do this, and we can actually answer these questions!” I might have done a little hop dance around the room to convey my excitement. But no, really. Stats are cool. Numbers are cool. They tell us stories about our world and the things in it. My goal this semester – to convey that to my students and get them in on the stats dance.