Heads or Tails?

The chat snap today was In a coin toss, do you usually choose heads or tails? 

I was introducing counterclaims, and my segue way was Just as there are two sides to every coin, there are also two sides to every argument (see what I did there?), but the hook was to record each student's answer and then flip a coin at the end to see who "won". 

An inveterate tails-picker myself, I wondered if I was imagining it, but as I was marking the Hs and Ts next to the names on my roster, I noticed something odd. It seemed like most of the boys were choosing heads and most of the girls were choosing tails. As soon as I was done teaching for the day, I had to crunch some numbers. 

Turns out that 55% of the kids chose heads over tails, which surprised me, because I thought it would be closer to the 50-50 split that occurs when you actually toss a coin. Digging deeper into the data, I found that a full 75% of the boys chose heads, and 67% of the girls chose tails. I have no explanation for these anecdotal results, but I do have a chance to conduct the experiment again tomorrow with my B-day classes. 

Are you on the edge of your seat?