Does Coin flip really has a 50–50 probability?
We all know that the probability of getting heads in a coin flip is 50%. Is it really true?
Let’s imagine a situation that you are making a bet with your friend. The game goes like this — you have to flip a coin 50 times. If tails land up more, then you have to pay $10 to your friend and vice-versa. And also the coin is a perfectly normal coin. No tricks involved in that. Now, the question is that, “Can you test your odds and go with the game?”
You would have studied probability in your high school. So, you know that you have a 50–50 chance to win, right? Why can’t you try your luck and go ahead with it?
But wait a min! Persi Diaconis wouldn’t recommend you to do so.
Diaconis is a professor of mathematics and statistics at Stanford University and, formerly, a professional magician. What he and his fellow researchers discovered is that most games of chance involving coins aren’t as even as you’d think. For example, even the 50/50 coin toss really isn’t 50/50 — it’s closer to 51/49, biased toward whatever side was up when the coin was thrown into the air.
Probability vs Physics:
He says that “Coin toss is not completely about probability”. It is also about physics, the coin, and how the “tosser” is actually throwing it. The majority of times, if a coin is a heads-up when it is flipped, it will remain heads-up when it lands. Diaconis has even trained himself to flip a coin and make it come up heads 10 out of 10 times.
A similar effect is seen if the coin is spun. We all know that a normal coin isn’t perfectly symmetrical. Because of the way most coins are made, the “heads” side can weigh more, which means it will fall on that side, leaving the other side up more often. Further, some magicians will have coins that are shaved, giving more weight to one side. So, the point is that it’s not 50/50 at all.
“Coin tossing is pretty close to fair,” he said.
But it’s not 50/50.
So, be careful before making a bet with your friend using a coin toss. Now, you know the physics and theory behind this. You can test it out with your friend and make the odds of 51% to be with you.
Thank you for reading!
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