Coins often have different designs or embossments on each side, i.e. a more detailed design or raised features on on side might also contribute to subtle differences in mass distribution or surface characteristics which affect the way coins land. Some coins also have thicker or more pronounced edges, which can affect the probability of actually landing on the edge versus landing flat on either face!
Does it also depend on how much wear and tear the coins have undergone in influencing the surface area of each side of the coin and accordingly the probability of the coin then landing on one side or the other? In other words you have 3 hoops of probabilistic outcome which one needs to overcome. No?
Coins often have different designs or embossments on each side, i.e. a more detailed design or raised features on on side might also contribute to subtle differences in mass distribution or surface characteristics which affect the way coins land. Some coins also have thicker or more pronounced edges, which can affect the probability of actually landing on the edge versus landing flat on either face!
The most interesting study on this subject that I've ever seen https://www.stat.berkeley.edu/users/aldous/157/Papers/diaconis_coinbias.pdf concluded that skilled individuals can subconsciously (or deliberately) control the result by how they hold and flip the coin, as well as how much rotational force they use. This manipulation can be subtle, influenced by psychological tendencies to achieve a specific result. The primary author Persi Diaconis https://en.wikipedia.org/wiki/Persi_Diaconis is a really interesting guy; a high school dropout who went in to earn a Harvard PhD in math and become a Stanford professor ... and magician! https://youtu.be/Obg7JPd6cmw?si=95yLcwHa-VaJiPlU and https://youtu.be/AYnJv68T3MM?si=ZRLWZLlMamOQUvOX .
Which is why the researchers used different coins of different denominations and currencies.
Does it also depend on how much wear and tear the coins have undergone in influencing the surface area of each side of the coin and accordingly the probability of the coin then landing on one side or the other? In other words you have 3 hoops of probabilistic outcome which one needs to overcome. No?