May 11, 2015

Biased coin - short tale with my children

Few days ago my both children had to follow an aerosol therapy. You know that thing called nebuliser which convert the medicine to fine mist, which you breathe in through a mask. While not intrusive at all, none of my both children (my son, 6 years old, and my daughter, 7 years old) is happy to follow. When I asked who will be the first to try it, both of them started to point their finger to each other. I didn't want to choose one of them, so I found a clever solution:

"Let's flip a coin! It's fair, and the one who's face will remain up after draw will be the first!"

Everybody was happy. They chose their side with no problem. My son choose the head and his sister the tail. We flip the coin. Head. My son was sad, but he accepted the result. However I started to encourage him.

"Hey, don't be sad. Next time it might come tail. Believe me. Look, if we draw it 
again it will come tail, just to show you".

And I flipped the coin again. Head. No very helpful for my case.

"Well, it happens by chance. But you have to believe me, it's fair. We will try again and it will be tail. Let's see."

I flipped again one more time. Head. Not a nice result. The bias sneaked into my mind. My confidence level started to drop. My children started to smile.

"This time will BE tail!"

Well, it was not. My children started to laugh at me. My karma points were out.

"Really, right now it will be TAIL!" 

And I started to stair at the coin in a strange way. I really wanted to control that damn coin to be reasonable. But I could not control that damn coin. Heads again. My children started to jump and laugh. To Gods of Random was laughing at me, also. I felt betrayed.

After some additional draws I had eight heads, not even a single tail. How can I tell him that is fair? The nine-th time I was hopeless. But the Gods were merciful. Tail. And another head and another tail. Pity consolation. I played my last card. I asked him:

"You see? It comes also tails!"

He looked at me in his own unique generous way, and whispered me:

"Yes. But the heads comes more often."

I lost the battle.

[A day later]

The same problem, same dilemma, same process. But this time the tail was up.My karma level started again to take some strictly positive values.